Check that AllocationMementos never get scavengend.

src/heap-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 507 matching lines @@
 
   // If the first word is a forwarding address, the object has already been
   // copied.
   if (first_word.IsForwardingAddress()) {
     HeapObject* dest = first_word.ToForwardingAddress();
     ASSERT(HEAP->InFromSpace(*p));
     *p = dest;
     return;
   }
 
+  // TODO(hpayer): temporary debugging code for issue 284577.
+  CHECK(object->map() != object->GetHeap()->allocation_memento_map());
   // Call the slow part of scavenge object.
   return ScavengeObjectSlow(p, object);
 }
 
 
 MaybeObject* Heap::AllocateEmptyJSArrayWithAllocationSite(
       ElementsKind elements_kind,
       Handle<AllocationSite> allocation_site) {
   return AllocateJSArrayAndStorageWithAllocationSite(elements_kind, 0, 0,
       allocation_site, DONT_INITIALIZE_ARRAY_ELEMENTS);
@@ skipping 343 matching lines @@
 DisallowAllocationFailure::~DisallowAllocationFailure() {
 #ifdef DEBUG
   HEAP->disallow_allocation_failure_ = old_state_;
 #endif
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_INL_H_