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

test/mjsunit/argument-assigned.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 113 matching lines @@
   function f(x) {
     function g(y, s) {
       eval(s);
     }
     arguments = {};
     g(991, "x = y;");
     return x;
   }
   assertEquals(991, f(7));
 })();