Revert "Clean up runtime functions for Maths."

This reverts r20307.

TBR=jarin@chromium.org

Review URL: https://codereview.chromium.org/214593005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20311 ce2b1a6d-e550-0410-aec6-3dcde31c8c00