Remove dangerous default parameter from machine Store operator.

test/cctest/compiler/test-machine-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 "test/cctest/cctest.h"
 
 #include "src/base/utils/random-number-generator.h"
 #include "src/compiler/graph-inl.h"
 #include "src/compiler/machine-operator-reducer.h"
 #include "test/cctest/compiler/value-helper.h"
@@ skipping 621 matching lines @@
   Node* index = R.Constant<int32_t>(4);
   Node* load = R.graph.NewNode(R.machine.Load(kMachineWord32), base, index);
 
   {
     MachineOperatorReducer reducer(&R.graph);
     Reduction reduction = reducer.Reduce(load);
     CHECK(!reduction.Changed());  // loads should not be reduced.
   }
 
   {
-    Node* store =
-        R.graph.NewNode(R.machine.Store(kMachineWord32), base, index, load);
+    Node* store = R.graph.NewNode(
+        R.machine.Store(kMachineWord32, kNoWriteBarrier), base, index, load);
     MachineOperatorReducer reducer(&R.graph);
     Reduction reduction = reducer.Reduce(store);
     CHECK(!reduction.Changed());  // stores should not be reduced.
   }
 }
 
 
 static void CheckNans(ReducerTester* R) {
   Node* x = R->Parameter();
   std::vector<double> nans = ValueHelper::nan_vector();
@@ skipping 116 matching lines @@
 // TODO(titzer): test MachineOperatorReducer for Int64Mul
 // TODO(titzer): test MachineOperatorReducer for Int64UMul
 // TODO(titzer): test MachineOperatorReducer for Int64Div
 // TODO(titzer): test MachineOperatorReducer for Int64UDiv
 // TODO(titzer): test MachineOperatorReducer for Int64Mod
 // TODO(titzer): test MachineOperatorReducer for Int64UMod
 // TODO(titzer): test MachineOperatorReducer for Int64Neg
 // TODO(titzer): test MachineOperatorReducer for ChangeInt32ToFloat64
 // TODO(titzer): test MachineOperatorReducer for ChangeFloat64ToInt32
 // TODO(titzer): test MachineOperatorReducer for Float64Compare