Merge up to 8597 to experimental/gc from the bleeding edge.

test/mjsunit/polymorph-arrays.js

 // Copyright 2011 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 157 matching lines @@
   store(sparse_js_array, 3, 258);
 
   assertEquals(258, object_array[3]);
   assertEquals(258, js_array[3]);
   assertEquals(258, sparse_js_array[3]);
   assertEquals(258, sparse_object_array[3]);
 }
 
 testPolymorphicLoads();
 testPolymorphicStores();