This removed a lot of copy-n-paste code and is very handy for some upcoming
changes (regarding predictable code size).

Review URL: https://codereview.chromium.org/11416133

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13034 ce2b1a6d-e550-0410-aec6-3dcde31c8c00