Remove lock check assertion for reorder

A previous commit (7e30ed6) added an assertion check to the reoder
code's `swap_relation_files` to ensure that proper locks are held on
the relations when updating their pg_class entries, per new
requirements in recent PostgreSQL releases. However, this check failed
because the function could be called on indexes as well as tables, and
indexes have different locking requirements.

The assertions aren't strictly needed because heap_update() has a
check of its own that will raise a warning if locking requirements are
not met (assuming the code is compiled with assertions enabled).

tsl/src/reorder.c

@@ -926,9 +926,6 @@ swap_relation_files(Oid r1, Oid r2, bool swap_toast_by_content, bool is_internal
 	Oid swaptemp;
 	char swptmpchr;
 
-	AssertSufficientPgClassUpdateLockHeld(r1);
-	AssertSufficientPgClassUpdateLockHeld(r2);
-
 	/* We need writable copies of both pg_class tuples. */
 	relRelation = table_open(RelationRelationId, RowExclusiveLock);