This migrates all the tests using ext/openssl/tests/streams_crypto_method.pem
to the certificate generator, so we can easily adjust needed parameters.
In particular, this makes the cert security level 2 compatible.
However, we still need to downgrade security_level to 1 in a number
of tests, because they are testing TLS < 1.2 connections.
- All streams-related code now lives in xp_ssl.c. Previously
stream code was split across both openssl.c and xp_ssl.c
- Folded superfluous php_openssl_structs.h into xp_ssl.c
- Server-specific options now set on SSL_CTX instead of SSL
- Deprecate SNI_server_name ctx option
- Miscellaneous refactoring