[turbofan] Remove locally constructed simplified builders.

src/compiler/js-typed-lowering.cc

Index: src/compiler/js-typed-lowering.cc
diff --git a/src/compiler/js-typed-lowering.cc b/src/compiler/js-typed-lowering.cc
index 815e372b3faeb3138241b31947793d38458e73aa..2f9a23a90f926d592456a7c4102d70e591d6f53a 100644
--- a/src/compiler/js-typed-lowering.cc
+++ b/src/compiler/js-typed-lowering.cc
@@ -22,7 +22,7 @@ namespace compiler {
 
 
 JSTypedLowering::JSTypedLowering(Editor* editor, JSGraph* jsgraph, Zone* zone)
-    : AdvancedReducer(editor), jsgraph_(jsgraph), simplified_(graph()->zone()) {
+    : AdvancedReducer(editor), jsgraph_(jsgraph) {
   for (size_t k = 0; k < arraysize(shifted_int32_ranges_); ++k) {
     double min = kMinInt / (1 << k);
     double max = kMaxInt / (1 << k);
@@ -1836,6 +1836,11 @@ CommonOperatorBuilder* JSTypedLowering::common() const {
 }
 
 
+SimplifiedOperatorBuilder* JSTypedLowering::simplified() const {
+  return jsgraph()->simplified();
+}
+
+
 MachineOperatorBuilder* JSTypedLowering::machine() const {
   return jsgraph()->machine();
 }