[turbofan] Use MachineRepresentation for PropertyCell access.

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"
 #include "src/elements-kind.h"
 
@@ skipping 177 matching lines @@
   // Provides access to arguments object fields.
   static FieldAccess ForArgumentsLength();
   static FieldAccess ForArgumentsCallee();
 
   // Provides access to FixedArray slots.
   static FieldAccess ForFixedArraySlot(size_t index);
 
   // Provides access to Context slots.
   static FieldAccess ForContextSlot(size_t index);
 
-  // Provides access to PropertyCell::value() field.
-  static FieldAccess ForPropertyCellValue();
-  static FieldAccess ForPropertyCellValue(Type* type);
-
   // Provides access to FixedArray elements.
   static ElementAccess ForFixedArrayElement();
   static ElementAccess ForFixedArrayElement(ElementsKind kind);
 
   // 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);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(AccessBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_ACCESS_BUILDER_H_