[turbofan] Machine operators are globally shared singletons.

src/compiler/change-lowering-unittest.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/change-lowering.h"
 #include "src/compiler/compiler-test-utils.h"
 #include "src/compiler/graph-unittest.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/compiler/simplified-operator.h"
@@ skipping 59 matching lines @@
 
   Node* Parameter(int32_t index = 0) {
     return graph()->NewNode(common()->Parameter(index), graph()->start());
   }
 
   Reduction Reduce(Node* node) {
     Typer typer(zone());
     JSGraph jsgraph(graph(), common(), &typer);
     CompilationInfo info(isolate(), zone());
     Linkage linkage(&info);
-    MachineOperatorBuilder machine(zone(), WordRepresentation());
+    MachineOperatorBuilder machine(WordRepresentation());
     ChangeLowering reducer(&jsgraph, &linkage, &machine);
     return reducer.Reduce(node);
   }
 
   SimplifiedOperatorBuilder* simplified() { return &simplified_; }
 
   Matcher<Node*> IsAllocateHeapNumber(const Matcher<Node*>& effect_matcher,
                                       const Matcher<Node*>& control_matcher) {
     return IsCall(
         _, IsHeapConstant(Unique<HeapObject>::CreateImmovable(
@@ skipping 375 matching lines @@
               IsIfTrue(AllOf(CaptureEq(&branch),
                              IsBranch(IsUint32LessThanOrEqual(
                                           val, IsInt32Constant(SmiMaxValue())),
                                       graph()->start()))),
               AllOf(CaptureEq(&if_false), IsIfFalse(CaptureEq(&branch))))));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8