Ensure that the KeyInfo.nXField value for ephemeral tables used to implement

ORDER BY or GROUP BY clauses is set correctly, so that the
sqlite3VdbeFindCompare() routine can choose the correct comparison function.
Add assert() statements to the high-speed comparison functions to detect
cases where they are inappropriately chosen.
Fix for ticket [f97c4637102a3ae72b7911].

FossilOrigin-Name: f7201bb0cdc9e1425c68599b32434de2231dca36

diff --cc manifest
index cabfaf39169edc7b30c3b1dd5d3a0a7e5a39c69e,88e87b25f8df24e2e2818da80cc29d9039c9f4f1..5ab9b699da5710d1cd5d4ae966fd28b8fdef11fd
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Fix\scompilation\son\sCygwin\swhen\sSQLITE_MAX_WORKER_THREADS\sis\sgreater\sthan\szero.
- D 2015-01-19T20:05:53.508
 -C There\sare\sasserts\sin\splace\snow\sthat\swill\sprevent\sa\srecurrence\sof\nticket\s[f97c4637102a3ae7].\s\sNevertheless,\sit\sis\sgood\sto\sadd\ssome\ntest\scases\sas\swell.
 -D 2015-01-19T21:10:53.444
++C Ensure\sthat\sthe\sKeyInfo.nXField\svalue\sfor\sephemeral\stables\sused\sto\simplement\nORDER\sBY\sor\sGROUP\sBY\sclauses\sis\sset\scorrectly,\sso\sthat\sthe\nsqlite3VdbeFindCompare()\sroutine\scan\schoose\sthe\scorrect\scomparison\sfunction.\nAdd\sassert()\sstatements\sto\sthe\shigh-speed\scomparison\sfunctions\sto\sdetect\ncases\swhere\sthey\sare\sinappropriately\schosen.\nFix\sfor\sticket\s[f97c4637102a3ae72b7911].
++D 2015-01-19T21:36:05.317
  F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
  F Makefile.in 5407a688f4d77a05c18a8142be8ae5a2829dd610
  F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@@ -1236,7 -1237,7 +1237,8 @@@ F tool/vdbe_profile.tcl 67746953071a9f8
  F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
  F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
  F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
- P 824328f9833d01fc155a9d0265ef41d338cf1ffb
- R 46d0fc0085c932a30f59bac1bd145cf7
- U mistachkin
- Z 998ddd7b1750b28ed4b199120a25244e
 -P c16bae5e699b851f4ca8414c5dfa5370b18f69f0
 -R e27a2655369428e59f07848a6b54ddd6
++P 2037442c582e51d85967bc911ea4a412eb4da573 e02959b9a0e1bacdd3939548d4434c042aacc2e6
++R 5021170f2a6880b445a702735148b9c6
++T +closed e02959b9a0e1bacdd3939548d4434c042aacc2e6
+ U drh
 -Z e964ea280030c93ae7b89ddabdb22c13
++Z b76cf3617d76194e2b83c38054737fb3

diff --cc manifest.uuid
index 5c080e945f1e112b005e9b1c216476b3331a674b,7c623bd1a89909094cd503bdfbd02500c436e61a..06d89b2c821d440c0172b32c7c2be95c507e9eb0
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 2037442c582e51d85967bc911ea4a412eb4da573
 -e02959b9a0e1bacdd3939548d4434c042aacc2e6
++f7201bb0cdc9e1425c68599b32434de2231dca36