Now skips built-in functions called from other built-in functions,
so only the initally called built-in function is exposed.

Review URL: http://codereview.chromium.org/7740021

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9018 ce2b1a6d-e550-0410-aec6-3dcde31c8c00