[turbofan] Restore basic write barrier elimination.

src/compiler/access-builder.h

 // 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.
 
 #ifndef V8_COMPILER_ACCESS_BUILDER_H_
 #define V8_COMPILER_ACCESS_BUILDER_H_
 
 #include "src/compiler/simplified-operator.h"
 
 namespace v8 {
@@ skipping 124 matching lines @@
   // Provides access to FixedArray elements.
   static ElementAccess ForFixedArrayElement();
 
   // Provides access to FixedDoubleArray elements.
   static ElementAccess ForFixedDoubleArrayElement();
 
   // Provides access to Fixed{type}TypedArray and External{type}Array elements.
   static ElementAccess ForTypedArrayElement(ExternalArrayType type,
                                             bool is_external);
 
-  // ===========================================================================
-  // Access to global per-isolate variables (based on external reference).
-
-  // Provides access to the backing store of a StatsCounter.
-  static FieldAccess ForStatsCounter();
-
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(AccessBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_ACCESS_BUILDER_H_