Merge bleeding edge into the GC branch up to 7948. The asserts

tools/gcmole/gccause.lua

 -- 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 40 matching lines @@
       end
    end
 end
 
 for name, _ in pairs(GC) do
    if name:match(P) then
       T = {}
       TrackCause(name)
    end
 end