betranshlp: Only check once, whether each node is in the right obstack.

ir/be/betranshlp.c

@@ -224,11 +224,11 @@ void be_enqueue_preds(ir_node *node)
  */
 static void fix_loops(ir_node *node)
 {
-	assert(node_is_in_irgs_storage(env.irg, node));
-
 	if (irn_visited_else_mark(node))
 		return;
 
+	assert(node_is_in_irgs_storage(env.irg, node));
+
 	bool changed = false;
 	if (! is_Block(node)) {
 		ir_node *block     = get_nodes_block(node);