REGTEST: quic: add ssl_reuse.vtc new QUIC test

REGTEST: quic: add ssl_reuse.vtc new QUIC test

Note that this test does not work with OpenSSL 3.5.0 QUIC API because
the callback set by SSL_CTX_sess_set_new_cb() (ssl_sess_new_srv_cb()) is not
called (at least for QUIC clients)

The role of this new QUIC test is to run the same SSL/TCP test as
reg-tests/ssl/ssl_reuse.vtc but with QUIC connections where applicable (only with
TLSv1.3).

To do so, this QUIC test uses the "include" vtc command to run ssl/ssl_reuse.vtc
It also sets the VTC_SOCK_TYPE environment variable with the "setenv" command and
"quic" as value. This will ask vtest2 to use QUIC sockets for all "fd@{...}"
addresses prefixed by "${VTC_SOCK_TYPE}+" socket type if VTC_SOCK_TYPE value is "quic".

The SSL/TCP is modified to set this environment variable with "setenv -ifunset"
from ssl/ssl_reuse.vtc with "stream" as value, if it not already set.

vtest2 must be used with this patch to support this new QUIC test:
https://github.com/vtest/VTest2/commit/9aa4d498dbd426adef8779c692a3e0865e55b9c2

Thanks to this latter patch, vtest2 retrieves the VTC_SOCK_TYPE environment variable
value, then it parses the vtc file to retrieve all the fd addresses prefixed by
"${VTC_SOCK_TYPE}+" and creates a QUIC socket or a TCP socket depending on this
variable value.