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

test/mjsunit/regress/regress-1521.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 27 matching lines @@
       };
       %OptimizeFunctionOnNextCall(g);
       return g;
     }
     assertEquals(3, f()());
   }
 }
 
 test(3);