FIPS tests changes for RHEL

FIPS tests changes for RHEL

Include MD5 feature detection in featuretest tool and use it in some
places. When RHEL distribution or Fedora ELN is in FIPS mode, then MD5
algorithm is unavailable completely and even hmac-md5 algorithm usage
will always fail. Work that around by checking MD5 works and if not,
skipping its usage.

Those changes were dragged as downstream patch bind-9.11-fips-tests.patch
in Fedora and RHEL.