The previous duplication is quite bad from an architectural point of
view. Furthermore, it messes up the output of --hydrogen-stats.

As remarked in a comment, there is still more unification work to do, but at
least this CL is a step in the right direction...

Review URL: https://codereview.chromium.org/12091016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13527 ce2b1a6d-e550-0410-aec6-3dcde31c8c00