[turbofan] Remove locally constructed simplified builders.

src/compiler/js-type-feedback-lowering.cc

Index: src/compiler/js-type-feedback-lowering.cc
diff --git a/src/compiler/js-type-feedback-lowering.cc b/src/compiler/js-type-feedback-lowering.cc
index b618bf65e022d53407d9678e8168e706bf1bba11..03f180513182335c36304ec1b6ee3e471a6ac905 100644
--- a/src/compiler/js-type-feedback-lowering.cc
+++ b/src/compiler/js-type-feedback-lowering.cc
@@ -16,10 +16,7 @@ namespace compiler {
 
 JSTypeFeedbackLowering::JSTypeFeedbackLowering(Editor* editor, Flags flags,
                                                JSGraph* jsgraph)
-    : AdvancedReducer(editor),
-      flags_(flags),
-      jsgraph_(jsgraph),
-      simplified_(graph()->zone()) {}
+    : AdvancedReducer(editor), flags_(flags), jsgraph_(jsgraph) {}
 
 
 Reduction JSTypeFeedbackLowering::Reduce(Node* node) {
@@ -114,6 +111,11 @@ MachineOperatorBuilder* JSTypeFeedbackLowering::machine() const {
   return jsgraph()->machine();
 }
 
+
+SimplifiedOperatorBuilder* JSTypeFeedbackLowering::simplified() const {
+  return jsgraph()->simplified();
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8