irnode: No need to set fields to 0 after OALLOCZ

ir/ir/irnode.c

@@ -87,9 +87,7 @@ ir_node *new_ir_node(dbg_info *db, ir_graph *irg, ir_node *block, ir_op *op,
 	res->op       = op;
 	res->mode     = mode;
 	res->irg      = irg;
-	res->visited  = 0;
 	res->node_idx = irg_register_node_idx(irg, res);
-	res->link     = NULL;
 
 	if (arity < 0) {
 		res->in = NEW_ARR_F(ir_node *, 1);  /* 1: space for block */