Make record_out and record_send extract type information from the passed

Make record_out and record_send extract type information from the passed
record object itself, rather than relying on a second OID argument to be
correct.  This patch just changes the function behavior and not the
catalogs, so it's OK to back-patch to 8.0.  Will remove the now-redundant
second argument in pg_proc in a separate patch in HEAD only.