tests/server: support bundle binary

tests/server: support bundle binary

Extend existing `--enable-test-bundles` and `-DCURL_TEST_BUNDLES=ON`
options to also bundle test server programs into a single binary. With
autotools, also bundle auxiliary libcurl sources for a "unity"-style
build.

It saves almost 10 minutes per run, across all CI jobs.
On average it makes `build tests` steps 25% faster.

With CMake, it brings down `testdeps` build steps to 32 to 37, from
45 to 64 before this patch, with unity. Without unity it brings it down
from 400-420 to 280-300. For comparison, without unity and bundles,
the number of build steps is around 1850.

With autotools the gain is possibly larger because this patch does unity
and bundle for test servers.

The total reduction of build steps / log lines is 12000. It's 44% of
reduction on average across all CI jobs.

Follow-up to 77401af4852103b215fe74989e89be61bbf435d2 #16695
Follow-up to 71cf0d1fca9e1f53524e1545ef0c08d174458d80 #14772

Comparison of 'build tests' targets in S(econds) and L(ines/steps),
between before and after this patch:

CI job                                    |BefS|AftS|Gain|BefL|AftL|Gain| Comments
:---------------------------------------- | -: | -: | -: | --:| --:| --:| :-------
GHA/windows                               |    |    |    |    |    |    |
Cygwin AM                                 |110 | 95 | 15 | 237|  88| 149| l(ines)
Cygwin CM                                 | 34 | 27 |  7 |  63|  36|  27| s(teps, with Ninja)
msys2, AM x86_64 !proxy                   | 35 | 21 | 14 | 255| 108| 147| l
msys2, AM x86_64 default                  | 35 | 22 | 13 | 255| 108| 147| l
msys2, CM x86_64 default                  | 14 | 11 |  3 |  63|  36|  27| s
msys2, AM x86_64 default R                | 41 | 29 | 12 | 245|  96| 149| l
mingw, AM x86_64 default                  | 69 | 33 | 36 | 331| 156| 175| l
mingw, AM x86_64 c-ares U                 | 69 | 33 | 36 | 331| 156| 175| l
mingw, CM x86_64 schannel c-ares U        | 32 | 24 |  8 |  63|  36|  27| s
mingw, CM clang-x86_64 gnutls             |  9 |  6 |  3 |  63|  36|  27| s
mingw, CM ucrt-x86_64 schannel R TrackMem | 43 | 35 |  8 |  64|  37|  27| s
mingw, CM clang-x86_64 openssl            | 20 | 18 |  2 |  63|  36|  27| s
mingw, CM ucrt-x86_64 schannel uwp        | 36 | 34 |  2 |  47|  34|  13| s
mingw, CM x86_64 schannel dev debug       | 32 | 24 |  8 |  64|  37|  27| s
mingw, CM i686 schannel R                 | 38 | 37 |  1 |  47|  34|  13| s
dl-mingw, CM 9.5.0-x86_64 schan           |102 | 94 |  8 |  63|  36|  27| s
dl-mingw, CM 7.3.0-x86_64 schan mbedtls U | 32 | 24 |  8 |  94|  60|  34| l
dl-mingw, CM 6.4.0-i686 schannel !unity   | 42 | 31 | 11 | 427| 297| 130| l (no unity, yes bundle)
linux-mingw, AM gcc                       |  - |  - |    |   -|   -|    |
linux-mingw, CM gcc                       | 12 | 10 |  2 |  46|  33|  13| s
mingw32ce, AM 4.4.0-arm schannel          |  - |  - |    |   -|   -|    |
mingw32ce, CM 4.4.0-arm schannel          | 30 | 31 | -1 |  81|  61|  20| l
msvc, CM x64-uwp openssl +examples        | 13 | 10 |  3 | 102|  68|  34| l
msvc, CM x64-windows openssl              | 13 | 10 |  3 | 102|  68|  34| l
msvc, CM x64-windows schannel MultiSSL U  | 13 | 10 |  3 | 102|  68|  34| l
msvc, CM x64-windows libressl             | 14 | 13 |  1 | 102|  68|  34| l
msvc, CM x64-windows boringssl            | 11 | 11 |  0 |  84|  64|  20| l
msvc, CM x64-windows wolfssl +examples    | 13 | 10 |  3 | 102|  68|  34| l
msvc, CM x64-windows mbedtls libssh       | 14 | 10 |  4 | 102|  68|  34| l
GHA/old-linux:                            |    |    |    |    |    |    |
linux (cmake & autoconf) AM               | 14 | 11 |  3 | 217|  75| 142| l
linux (cmake & autoconf) CM               | 15 | 13 |  2 | 545| 380| 165| l
GHA/non-native:                           |    |    |    |    |    |    |
AmigaOS, AM gcc AmiSSL m68k               |  - |  - |    |   -|   -|    |
AmigaOS, CM gcc AmiSSL m68k               |  8 |  7 |  1 |  78|  58|  20| l
Android 21, AM openssl arm64              |  7 |  5 |  2 | 222|  80| 142| l
Android 21, CM openssl arm64              |  4 |  5 | -1 |  81|  61|  20| l
Android 35, AM openssl arm64              |  7 |  5 |  2 | 222|  80| 142| l
Android 35, CM boringssl !zstd arm64      |  4 |  3 |  1 |  81|  61|  20| l
Android 35, CM openssl arm64              |  5 |  4 |  1 |  81|  61|  20| l
FreeBSD, AM clang openssl arm64           |  - |  - |    |   -|   -|    |
FreeBSD, AM clang openssl x86_64          |  7 |  3 |  4 | 513| 133| 380| l
FreeBSD, CM clang openssl !unity !bundle..| 49 | 47 |  2 |1841|1841|    | s (no unity, no bundle)
FreeBSD, CM clang openssl arm64           |  - |  - |    |   -|   -|    |
MS-DOS, AM djgpp openssl i586             |  - |  - |    |   -|   -|    |
MS-DOS, CM djgpp openssl i586             |  6 |  7 | -1 |  45|  32|  13| s
NetBSD, CM clang openssl x86_64           | 15 | 13 |  2 |  62|  35|  27| s
OmniOS, AM gcc openssl amd64              | 20 | 11 |  9 | 216|  74| 142| l
OpenBSD, CM clang libressl x86_64         |  9 |  7 |  2 |  62|  35|  27| s
iOS, AM libressl arm64                    |  6 |  3 |  3 | 217|  68| 149| l
iOS, CM libressl arm64                    | 10 | 10 |  0 | 236| 175|  61| l
iOS, CM-Xcode libressl arm64              | 13 |  8 |  5 | 899| 627| 272| l
GHA/linux:                                |    |    |    |    |    |    |
AM bearssl                                |  9 |  8 |  1 | 258| 111| 147| l
AM bearssl clang                          |  6 |  4 |  2 | 258| 111| 147| l
AM libressl heimdal                       | 11 |  8 |  3 | 267| 120| 147| l
CM libressl heimdal valgrind              |  8 |  5 |  3 |  62|  35|  27| s
AM libressl clang                         |  7 |  4 |  3 | 258| 111| 147| l
AM wolfssl-all                            | 11 |  8 |  3 | 258| 111| 147| l
AM wolfssl-opensslextra valgrind          | 11 |  7 |  4 | 258| 111| 147| l
AM mbedtls valgrind                       | 10 |  7 |  3 | 258| 111| 147| l
AM mbedtls clang                          |  6 |  3 |  3 | 258| 111| 147| l
CM mbedtls                                |  7 |  6 |  1 |  62|  35|  27| s
CM mbedtls-pkg                            |  7 |  7 |  0 |  62|  35|  27| s
CM mbedtls-pkg !pc                        |  - |  - |    |   -|   -|    |
AM msh3                                   | 10 |  7 |  3 | 258| 111| 147| l
CM msh3                                   |  7 |  7 |  0 |  62|  35|  27| s
AM awslc                                  | 18 | 15 |  3 | 247|  98| 149| l
CM awslc                                  | 13 | 11 |  2 | 400| 277| 123| s (no unity, yes bundle)
AM openssl default                        | 10 |  7 |  3 | 258| 111| 147| l
AM openssl libssh2 sync-resolver valgrind | 10 |  7 |  3 | 258| 111| 147| l
AM openssl                                | 11 |  7 |  4 | 258| 111| 147| l
AM openssl -O3 valgrind                   | 26 | 21 |  5 | 258| 111| 147| l
AM openssl clang krb5                     |  7 |  3 |  4 | 265| 118| 147| l
CM openssl clang krb5 LTO                 |  - |  - |    |   -|   -|    |
AM openssl !ipv6 !--libcurl               | 10 |  7 |  3 | 258| 111| 147| l
AM openssl https-only                     | 11 |  8 |  3 | 258| 111| 147| l
CM openssl torture !FTP                   |  7 |  6 |  1 |  62|  35|  27| s
CM openssl torture FTP                    |  8 |  6 |  2 |  62|  35|  27| s
AM openssl i686                           | 12 |  9 |  3 | 258| 111| 147| l
AM !ssl !http !smtp !imap                 | 10 |  7 |  3 | 258| 111| 147| l
AM clang-tidy                             |  - |  - |    |   -|   -|    |
AM scanbuild                              |  - |  - |    |   -|   -|    |
AM address-sanitizer                      | 10 |  6 |  4 | 258| 111| 147| l
AM thread-sanitizer                       |  7 |  4 |  3 | 258| 111| 147| l
AM memory-sanitizer                       | 10 |  6 |  4 | 258| 111| 147| l
AM event-based                            | 10 |  7 |  3 | 253| 106| 147| l
AM duphandle                              | 10 |  8 |  2 | 253| 106| 147| l
AM rustls valgrind                        | 10 |  8 |  2 | 258| 111| 147| l
CM rustls                                 |  7 |  5 |  2 |  62|  35|  27| s
AM IntelC openssl                         | 18 | 14 |  4 | 572| 282| 290| l
AM Slackware openssl gssapi gcc           | 17 | 14 |  3 | 252| 103| 149| l
AM Alpine MUSL https-rr                   | 15 | 11 |  4 | 266| 119| 147| l
AM Alpine MUSL c-ares https-rr            | 15 | 11 |  4 | 266| 119| 147| l
GHA/linux-http3:                          |    |    |    |    |    |    |
AM quictls                                | 12 |  8 |  4 | 258| 111| 147| l
AM gnutls                                 | 11 |  8 |  3 | 257| 110| 147| l
AM wolfssl                                | 11 |  9 |  2 | 257| 110| 147| l
CM wolfssl                                |  8 |  7 |  1 |  62|  35|  27| s
AM openssl-quic                           | 11 |  8 |  3 | 257| 110| 147| l
AM quiche                                 | 11 |  9 |  2 | 257| 110| 147| l
CM quiche                                 |  8 |  6 |  2 |  62|  35|  27| s
GHA/macos:                                |    |    |    |    |    |    |
AM clang !ssl !debug brotli zstd          |  5 |  3 |  2 | 218|  69| 149| l
AM clang !ssl                             |  4 |  5 | -1 | 227|  80| 147| l
AM clang !ssl libssh2 AppleIDN            |  5 |  1 |  4 | 227|  80| 147| l
AM clang OpenSSL libssh c-ares            |  4 |  2 |  2 | 227|  80| 147| l
AM clang !ssl c-ares                      |  4 |  5 | -1 | 227|  80| 147| l
AM clang !ssl HTTP-only                   |  4 |  2 |  2 | 222|  75| 147| l
AM clang SecureTransport libssh2          |  3 |  3 |  0 | 227|  80| 147| l
AM clang SecureTransport libssh2 10.12    |  4 |  2 |  2 | 227|  80| 147| l
AM clang LibreSSL +examples               |  5 |  2 |  3 | 227|  80| 147| l
AM clang OpenSSL                          |  6 |  1 |  5 | 227|  80| 147| l
AM clang OpenSSL event-based              |  5 |  3 |  2 | 227|  80| 147| l
AM clang quictls libssh2 !ldap 10.15      |  4 |  2 |  2 | 227|  80| 147| l
CM clang OpenSSL gsasl rtmp AppleIDN      |  2 |  2 |  0 |  45|  32|  13| s
CM clang OpenSSL AppleIDN clang-tidy +e   |150 | 76 | 74 | 400| 277| 123| s (clang-tidy)
CM clang quictls +static libssh +examples |  2 |  2 |  0 |  45|  32|  13| s
CM clang SecureTransport debug            |  2 |  2 |  0 |  62|  35|  27| s
CM clang LibreSSL !ldap heimdal c-ares +e |  4 |  2 |  2 |  45|  32|  13| s
CM clang wolfSSL !ldap brotli zstd        |  1 |  2 | -1 |  45|  32|  13| s
CM clang mbedTLS openldap brotli zstd     |  1 |  2 | -1 |  45|  32|  13| s
CM clang GnuTLS !ldap krb5                |  0 |  1 |  0 |  45|  32|  13| s
CM clang OpenSSL torture !FTP             |  2 |  1 |  1 |  61|  34|  27| s
CM clang OpenSSL torture FTP              |  2 |  1 |  1 |  61|  34|  27| s
AM llvm@15 OpenSSL libssh                 |  5 |  4 |  1 | 227|  80| 147| l
CM llvm@15 OpenSSL gsasl rtmp AppleIDN    |  3 |  2 |  1 |  45|  32|  13| s
CM llvm@15 quictls +static libssh +e      |  2 |  2 |  0 |  45|  32|  13| s
CM llvm@15 SecureTransport debug          |  3 |  2 |  1 |  62|  35|  27| s
CM llvm@15 LibreSSL !ldap heimdal c-ares..|  3 |  1 |  2 |  45|  32|  13| s
CM llvm@15 wolfSSL !ldap brotli zstd      |  3 |  2 |  1 |  45|  32|  13| s
CM llvm@15 mbedTLS openldap brotli zstd   |  2 |  2 |  0 |  45|  32|  13| s
CM llvm@15 GnuTLS !ldap krb5              |  2 |  1 |  1 |  45|  32|  13| s
AM gcc-12 !ssl !debug                     | 18 | 12 |  6 | 218|  69| 149| l
AM gcc-12 SecureTransport libssh2         | 13 |  6 |  7 | 227|  80| 147| l
CM gcc-12 OpenSSL gsasl rtmp AppleIDN     |  7 |  5 |  2 |  45|  32|  13| s
CM gcc-12 quictls +static libssh +e       |  8 |  6 |  2 |  45|  32|  13| s
CM gcc-12 SecureTransport debug           |  8 |  6 |  2 |  62|  35|  27| s
CM gcc-12 LibreSSL !ldap heimdal c-ares...|  7 |  6 |  1 |  45|  32|  13| s
CM gcc-12 wolfSSL !ldap brotli zstd       | 16 |  6 | 10 |  45|  32|  13| s
CM gcc-12 mbedTLS openldap brotli zstd    | 11 |  6 |  5 |  45|  32|  13| s
CM gcc-12 GnuTLS !ldap krb5               |  7 |  5 |  2 |  45|  32|  13| s
AppVeyor:                                 |    |    |    |    |    |    |
VS2008 D x86 OpenSSL + Schannel SH +e     | 56 | 39 | 17 |  21|  14|   7| s (VCBuild)
VS2010 D x64 Schannel SH +e               | 14 | 12 |  2 | 105|  78|  27| l
VS2012 R x86 OpenSSL + Schannel SH        | 23 | 21 |  2 |  84|  64|  20| l
VS2013 D x64 OpenSSL SH Build-only        |  - |  - |    |   -|   -|    | (no build tests)
VS2015 D x64 OpenSSL ST Build-only        |  - |  - |    |   -|   -|    | (no build tests)
VS2017 D x64 OpenSSL SH Build-only        |  - |  - |    |   -|   -|    | (no build tests)
VS2019 D x64 OpenSSL + Schannel SH        | 33 | 26 |  7 |  81|  61|  20| l
VS2022 D x64 !SSL ST                      | 32 | 25 |  7 |  79|  59|  20| l
VS2022 D x64 !SSL ST HTTP-only            | 33 | 22 | 11 |  79|  59|  20| l
VS2022 R arm64 Schannel ST                | 74 | 69 |  5 |  79|  59|  20| l
VS2022 R x64 Schannel SH U DBGBLD !CURLDBG| 66 | 61 |  5 |  78|  58|  20| l
VS2022 D x64 Schannel ST U                | 34 | 25 |  9 |  79|  59|  20| l
VS2022 D x64 Schannel ST U clang-cl +e    | 42 | 34 |  8 |  53|  40|  13| l
VS2022 R x64 OpenSSL SH                   | 60 | 58 |  2 |  83|  63|  20| l
Total                                     |2394|1807|-587| 26k| 14k|-12k|
in %                                      |    |    |-24%|    |    |-45%|
in minutes                                |    |    |9m47|    |    |    |

Before:
GHA/windows: https://github.com/curl/curl/actions/runs/13854983424
GHA/old-linux: https://github.com/curl/curl/actions/runs/13854983399
GHA/non-native: https://github.com/curl/curl/actions/runs/13854983427
GHA/linux-http3: https://github.com/curl/curl/actions/runs/13854983409
GHA/linux: https://github.com/curl/curl/actions/runs/13854983406
GHA/macos: https://github.com/curl/curl/actions/runs/13854983401
Appveyor: https://ci.appveyor.com/project/curlorg/curl/builds/51703551

After:
GHA/windows: https://github.com/curl/curl/actions/runs/13860433850?pr=15000
GHA/old-linux: https://github.com/curl/curl/actions/runs/13860433809?pr=15000
GHA/non-native: https://github.com/curl/curl/actions/runs/13860433828?pr=15000
GHA/linux-http3: https://github.com/curl/curl/actions/runs/13860433806?pr=15000
GHA/linux: https://github.com/curl/curl/actions/runs/13860433848?pr=15000
GHA/macos: https://github.com/curl/curl/actions/runs/13860433835?pr=15000
Appveyor: https://ci.appveyor.com/project/curlorg/curl/builds/51704222

Closes #15000