Revert of Internalize strings in-place

src/ic/ic.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/ic/ic.h"
 
 #include <iostream>
 
 #include "src/accessors.h"
 #include "src/api-arguments-inl.h"
@@ skipping 1560 matching lines @@
     if (std::isnan(value)) {
       key = isolate->factory()->nan_string();
     } else {
       int int_value = FastD2I(value);
       if (value == int_value && Smi::IsValid(int_value)) {
         key = handle(Smi::FromInt(int_value), isolate);
       }
     }
   } else if (key->IsUndefined(isolate)) {
     key = isolate->factory()->undefined_string();
-  } else if (key->IsString()) {
-    key = isolate->factory()->InternalizeString(Handle<String>::cast(key));
   }
   return key;
 }
 
 void KeyedLoadIC::UpdateLoadElement(Handle<HeapObject> receiver) {
   Handle<Map> receiver_map(receiver->map(), isolate());
   DCHECK(receiver_map->instance_type() != JS_VALUE_TYPE &&
          receiver_map->instance_type() != JS_PROXY_TYPE);  // Checked by caller.
   MapHandleList target_receiver_maps;
   TargetMaps(&target_receiver_maps);
@@ skipping 1621 matching lines @@
     DCHECK_EQ(LookupIterator::INTERCEPTOR, it.state());
     it.Next();
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result,
                                        Object::GetProperty(&it));
   }
 
   return *result;
 }
 }  // namespace internal
 }  // namespace v8