Set LastAdded to kNoneAdded in RawCopy.

src/objects-inl.h

 // 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 3505 matching lines @@
 
   set_instance_descriptors(descriptors);
 
   for (int i = 0; i < len; ++i) {
     if (descriptors->GetDetails(i).index() == len) {
       SetLastAdded(i);
       break;
     }
   }
 
-  ASSERT(len == 0 ||
+  ASSERT((len == 0 && LastAdded() == kNoneAdded) ||
          len == descriptors->GetDetails(LastAdded()).index());
 }
 
 
 SMI_ACCESSORS(Map, bit_field3, kBitField3Offset)
 
 
 void Map::ClearDescriptorArray(Heap* heap, WriteBarrierMode mode) {
   Object* back_pointer = GetBackPointer();
 #ifdef DEBUG
@@ skipping 1853 matching lines @@
 #undef WRITE_UINT32_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_