they do nothing.  The frame is currently always spilled, so they were
not doing anything useful.

The call sites have been left alone to mark where spills will
eventually be needed if we begin doing register allocation on ARM.

Review URL: http://codereview.chromium.org/164136

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2644 ce2b1a6d-e550-0410-aec6-3dcde31c8c00