[turbofan] Machine operators are globally shared singletons.

src/compiler/machine-operator-reducer-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/base/bits.h"
 #include "src/compiler/graph-unittest.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator-reducer.h"
 #include "src/compiler/typer.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 class MachineOperatorReducerTest : public GraphTest {
  public:
   explicit MachineOperatorReducerTest(int num_parameters = 2)
-      : GraphTest(num_parameters), machine_(zone()) {}
+      : GraphTest(num_parameters) {}
 
  protected:
   Reduction Reduce(Node* node) {
     Typer typer(zone());
     JSGraph jsgraph(graph(), common(), &typer);
     MachineOperatorReducer reducer(&jsgraph);
     return reducer.Reduce(node);
   }
 
   MachineOperatorBuilder* machine() { return &machine_; }
@@ skipping 501 matching lines @@
       r = Reduce(graph()->NewNode(common()->Projection(0), add));
       ASSERT_TRUE(r.Changed());
       EXPECT_THAT(r.replacement(), IsInt32Constant(z));
     }
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8