Prefill pre-allocated memory of folded allocation with one pointer fillers when heap verifier is on.

BUG=
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/19723004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15798 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Track all non-hole global constants.

R=mvstanton@chromium.org

Review URL: https://chromiumcodereview.appspot.com/19784004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15803 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Limit the amount of memory that can be folded together.

BUG=
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/19804002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15804 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Exclude const-strings from global constant tracking.

R=mvstanton@chromium.org

Review URL: https://chromiumcodereview.appspot.com/19576008

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15805 ce2b1a6d-e550-0410-aec6-3dcde31c8c00