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>
This is done by taking one vector, "corrupting" last bit of the
tag value and verifying that decrypt fails.
Reviewed-by: Emilia Käsper <emilia@openssl.org>