Stop test/shlibloadtest.c from failing in a regression test

When doing a regression test, it's obvious that the version
test/shlibloadtest is built for will not be the same as the library
version.  So we change the test to check for assumed compatibility.

Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5620)