Do not serialize stack limits.

This is part of making snapshots reproducable, more to come...

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/33193004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17313 ce2b1a6d-e550-0410-aec6-3dcde31c8c00