Cleanup leftover definitions in HGraph.

R=danno@chromium.org

Review URL: https://codereview.chromium.org/19154002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15654 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This does not match ES6 spec but is the behavior in both Firefox and WebKit/Blink.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/19086003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15655 ce2b1a6d-e550-0410-aec6-3dcde31c8c00