Temporarily disable optimization for StringWrappers to use native valueOf

src/x64/full-codegen-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2989 matching lines @@
   // prototype is the un-modified String prototype. If not result is false.
   __ movq(rcx, FieldOperand(rbx, Map::kPrototypeOffset));
   __ testq(rcx, Immediate(kSmiTagMask));
   __ j(zero, if_false);
   __ movq(rcx, FieldOperand(rcx, HeapObject::kMapOffset));
   __ movq(rdx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
   __ movq(rdx, FieldOperand(rdx, GlobalObject::kNativeContextOffset));
   __ cmpq(rcx,
           ContextOperand(rdx, Context::STRING_FUNCTION_PROTOTYPE_MAP_INDEX));
   __ j(not_equal, if_false);
-  // Set the bit in the map to indicate that it has been checked safe for
-  // default valueOf and set true result.
-  __ or_(FieldOperand(rbx, Map::kBitField2Offset),
-         Immediate(1 << Map::kStringWrapperSafeForDefaultValueOf));
   __ jmp(if_true);
 
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
   context()->Plug(if_true, if_false);
 }
 
 
 void FullCodeGenerator::EmitIsFunction(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   ASSERT(args->length() == 1);
@@ skipping 1858 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64