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

test/mjsunit/numops-fuzz.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 4589 matching lines @@
   assertEquals(4, x >>= (tmp = -2577728327, tmp));
   assertEquals(16, x *= (x<<((2622323372.580596)*(tmp = -1947643367, tmp))));
   assertEquals(33554432, x <<= (tmp = -2938370507, tmp));
   assertEquals(-2399497018.987414, x -= (tmp = 2433051450.987414, tmp));
   assertEquals(1, x /= x);
   assertEquals(2, x <<= x);
   assertEquals(0, x >>= (x&x));
   assertEquals(0, x <<= x);
 }
 f();