Since we already have only one LIR class, it does not make much sense to separate
them at the HIR level.
Review URL: http://codereview.chromium.org/8426005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9846 ce2b1a6d-e550-0410-aec6-3dcde31c8c00