Do not include native Javascript in ExecutionState frames.

When a debug event is triggered, the ExecutionState object should not
expose native JS code.

R=aandrey@chromium.org

Review URL: https://codereview.chromium.org/429453005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22849 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Move a bunch of GC related files to heap/ subdirectory

BUG=none
R=hpayer@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/437993003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22850 ce2b1a6d-e550-0410-aec6-3dcde31c8c00