Fix test_sslcorrupt when using TLSv1.3

The test loops through all the ciphers, attempting to test each one in turn.
However version negotiation happens before cipher selection, so with TLSv1.3
switched on if we use a non-TLSv1.3 compatible cipher suite we get "no
share cipher".

Reviewed-by: Rich Salz <rsalz@openssl.org>