[turbofan] Address the useless overflow bit materialization.

src/compiler/representation-change.cc

Index: src/compiler/representation-change.cc
diff --git a/src/compiler/representation-change.cc b/src/compiler/representation-change.cc
index 61f363e77fe8a41b3ec1cf0f794d54de25252739..d05fa19a4d988fd86d2b5b869c6eb891a97f5275 100644
--- a/src/compiler/representation-change.cc
+++ b/src/compiler/representation-change.cc
@@ -604,9 +604,9 @@ const Operator* RepresentationChanger::Int32OverflowOperatorFor(
     IrOpcode::Value opcode) {
   switch (opcode) {
     case IrOpcode::kSpeculativeNumberAdd:  // Fall through.
-      return machine()->Int32AddWithOverflow();
+      return simplified()->CheckedInt32Add();
     case IrOpcode::kSpeculativeNumberSubtract:  // Fall through.
-      return machine()->Int32SubWithOverflow();
+      return simplified()->CheckedInt32Sub();
     default:
       UNREACHABLE();
       return nullptr;