Enhance ssltestlib's create_ssl_ctx_pair to take min and max proto version

Have all test programs using that function specify those versions.
Additionally, have the remaining test programs that use SSL_CTX_new
directly specify at least the maximum protocol version.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5663)