Add a test to exercise the use of s_server with "-cert_chain" to
construct an ocsp request.
This new functionality was added in PR #22192.
Testing:
make V=1 TESTS='test_ocsp_cert_chain' test
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/23101)
