[turbofan] Make Node::set_op safer via wrapper.

src/compiler/simplified-operator-reducer.cc

Index: src/compiler/simplified-operator-reducer.cc
diff --git a/src/compiler/simplified-operator-reducer.cc b/src/compiler/simplified-operator-reducer.cc
index 30bf47e29363fb076b6685bc342dc5b7dd0820b0..a7f790563ebfe89672f7f16fe26a17dff4626e24 100644
--- a/src/compiler/simplified-operator-reducer.cc
+++ b/src/compiler/simplified-operator-reducer.cc
@@ -100,8 +100,8 @@ Reduction SimplifiedOperatorReducer::Change(Node* node, const Operator* op,
                                             Node* a) {
   DCHECK_EQ(node->InputCount(), OperatorProperties::GetTotalInputCount(op));
   DCHECK_LE(1, node->InputCount());
-  node->set_op(op);
   node->ReplaceInput(0, a);
+  NodeProperties::ChangeOp(node, op);
   return Changed(node);
 }