Instead of adding an extra AST node we can just use an auxiliary
bailout id for named and keyed property count operations.
Review URL: http://codereview.chromium.org/6810015

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7524 ce2b1a6d-e550-0410-aec6-3dcde31c8c00