Revert "Add FINAL and OVERRIDE macros for C++11 final/override."

This reverts commit r16222 for not using V8_ prefix.

TBR=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/23301006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16230 ce2b1a6d-e550-0410-aec6-3dcde31c8c00