Call JS functions via native context instead of js builtins object.

src/code-stubs-hydrogen.cc

 // Copyright 2012 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/code-stubs.h"
 
 #include "src/bailout-reason.h"
 #include "src/field-index.h"
 #include "src/hydrogen.h"
 #include "src/ic/ic.h"
@@ skipping 2173 matching lines @@
       inline_or_runtime.Then();
       {
         // Found a cached index, load property inline.
         Push(Add<HLoadFieldByIndex>(receiver, Pop()));
       }
       inline_or_runtime.Else();
       {
         // KeyedLookupCache miss; call runtime.
         Add<HPushArguments>(receiver, key);
         Push(Add<HCallRuntime>(
-            isolate()->factory()->empty_string(),
             Runtime::FunctionForId(is_strong(casted_stub()->language_mode())
                                        ? Runtime::kKeyedGetPropertyStrong
                                        : Runtime::kKeyedGetProperty),
             2));
       }
       inline_or_runtime.End();
     }
     if_dict_properties.End();
   }
   index_name_split.End();
 
   return Pop();
 }
 
 
 Handle<Code> KeyedLoadGenericStub::GenerateCode() {
   return DoGenerateCode(this);
 }
 
 }  // namespace internal
 }  // namespace v8