Skip ssl-tests/19-mac-then-encrypt.conf for no-tls1_2

The second set of tests in that configuration uses the AES-SHA256
ciphers, which are only available for TLS 1.2.  Thus, when TLS 1.2
is disabled, there are no ciphers available and the handshake fails
with an internal error.  Apply the same treatment as for
13-fragmentation.conf, which uses the same ciphers.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4526)