Move fasl version check earlier.

Move fasl version check earlier.

This breaks INHIBIT_FASL_VERSION_CHECK -- but that was already broken
so that Scheme would abort (!) before even getting to the check,
because of the conditional in fasl_object_address which is called by
decode_fasl_header.

If someone wants to revive INHIBIT_FASL_VERSION_CHECK, be my guest,
though it might be easier to do whatever you're trying to do with the
portable fasdumper instead.