Fix bogus assertion in SetFastDoubleElements.

src/objects.cc

 // Copyright 2013 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 12447 matching lines @@
       SetFastDoubleElementsCapacityAndLength(object, new_capacity, index + 1);
       FixedDoubleArray::cast(object->elements())->set(index, double_value);
       object->ValidateElements();
       return value;
     }
   }
 
   // Otherwise default to slow case.
   ASSERT(object->HasFastDoubleElements());
   ASSERT(object->map()->has_fast_double_elements());
-  ASSERT(object->elements()->IsFixedDoubleArray());
+  ASSERT(object->elements()->IsFixedDoubleArray() ||
+         object->elements()->length() == 0);
 
   NormalizeElements(object);
   ASSERT(object->HasDictionaryElements());
   return SetElement(object, index, value, NONE, strict_mode, check_prototype);
 }
 
 
 Handle<Object> JSReceiver::SetElement(Handle<JSReceiver> object,
                                       uint32_t index,
                                       Handle<Object> value,
@@ skipping 4005 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal