Change OpenSSL::Test to be an extension of Test::More

It became tedious as well as error prone to have all recipes use
Test::More as well as OpenSSL::Test.  The easier way is to make
OpenSSL::Test an extension of Test::More, thereby having all version
checks as well as future checks firmly there.  Additionally, that
allows us to extend existing Test::More functions if the need would
arise.

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