Whenever we use a fixed temp at a call that can eagerly deopt we
now allow fixed register exclusively to avoid any overlap.

Review URL: http://codereview.chromium.org/6479014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6714 ce2b1a6d-e550-0410-aec6-3dcde31c8c00