Stop a TLSv1.3 server emitting an unsolicited PSK extension

Stop a TLSv1.3 server emitting an unsolicited PSK extension

If we attempt to accept a connection on an SSL object, and the
application has set an SSL_SESSION on that SSL object then we
can mistakenly believe that we are resuming and
emit an unsolicited PSK extension back to the client.

This can especially happen when using SSL_clear() which leaves
any SSL_SESSION associated with the SSL object.

See
https://github.com/openssl/openssl/discussions/27563#discussioncomment-13049352
and
https://github.com/openssl/openssl/discussions/24567

Reviewed-by: Todd Short <todd.short@me.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/27584)