[turbofan] Remove locally constructed simplified builders.

src/compiler/simplified-operator-reducer.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/simplified-operator-reducer.h"
 
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/operator-properties.h"
 #include "src/conversions-inl.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 SimplifiedOperatorReducer::SimplifiedOperatorReducer(JSGraph* jsgraph)
-    : jsgraph_(jsgraph), simplified_(jsgraph->zone()) {}
+    : jsgraph_(jsgraph) {}
 
 
 SimplifiedOperatorReducer::~SimplifiedOperatorReducer() {}
 
 
 Reduction SimplifiedOperatorReducer::Reduce(Node* node) {
   switch (node->opcode()) {
     case IrOpcode::kBooleanNot: {
       HeapObjectMatcher m(node->InputAt(0));
       if (m.HasValue()) {
@@ skipping 100 matching lines @@
 Graph* SimplifiedOperatorReducer::graph() const { return jsgraph()->graph(); }
 
 
 MachineOperatorBuilder* SimplifiedOperatorReducer::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8