The spec omits the receiver arg with the idea arrow functions with lexical |this| will obviate the need for it.

BUG=
R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/23727006

Patch from Rafael Weinstein <rafaelw@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16644 ce2b1a6d-e550-0410-aec6-3dcde31c8c00