Revert "Optimize function across closures."

This reverts r25102.

TBR=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/699143002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25104 ce2b1a6d-e550-0410-aec6-3dcde31c8c00