Run `tor_tls_cert_matches_key()` Test Suite with both OpenSSL and NSS.
This patch lifts the `tor_tls_cert_matches_key()` tests out of the
OpenSSL specific TLS test suite and moves it into the generic TLS test
suite that is executed for both OpenSSL and NSS.
This patch is largely a code movement, but we had to rewrite parts of
the test to avoid using OpenSSL specific data-types (such as `X509 *`)
and replace it with the generic Tor abstraction type
(`tor_x509_cert_impl_t *`).
This patch is part of the fix for TROVE-2020-001.
See: https://bugs.torproject.org/33119