Fix HeapTupleSatisfiesVacuum on aborted updater xacts

By using only the macro that checks infomask bits
HEAP_XMAX_IS_LOCKED_ONLY to verify whether a multixact is not an
updater, and not the full HeapTupleHeaderIsOnlyLocked, it would come to
the wrong result in case of a multixact containing an aborted update;
therefore returning the wrong result code.  This would cause predicate.c
to break completely (as in bug report #8273 from David Leverton), and
certain index builds would misbehave.  As far as I can tell, other
callers of the bogus routine would make harmless mistakes or not be
affected by the difference at all; so this was a pretty narrow case.

Also, no other user of the HEAP_XMAX_IS_LOCKED_ONLY macro is as
careless; they all check specifically for the HEAP_XMAX_IS_MULTI case,
and they all verify whether the updater is InvalidXid before concluding
that it's a valid updater.  So there doesn't seem to be any similar bug.

Author: alvherre

src/backend/utils/time/tqual.c

@@ -1287,7 +1287,9 @@ HeapTupleSatisfiesVacuum(HeapTupleHeader tuple, TransactionId OldestXmin,
 		{
 			if (tuple->t_infomask & HEAP_XMAX_INVALID)	/* xid invalid */
 				return HEAPTUPLE_INSERT_IN_PROGRESS;
-			if (HEAP_XMAX_IS_LOCKED_ONLY(tuple->t_infomask))
+			/* only locked? run infomask-only check first, for performance */
+			if (HEAP_XMAX_IS_LOCKED_ONLY(tuple->t_infomask) ||
+				HeapTupleHeaderIsOnlyLocked(tuple))
 				return HEAPTUPLE_INSERT_IN_PROGRESS;
 			/* inserted and then deleted by same xact */
 			return HEAPTUPLE_DELETE_IN_PROGRESS;