Fix webkit getOwnPropertyNames test after r24706 removed Array.prototype.values

TBR=danno@chromium.org

Review URL: https://codereview.chromium.org/664613004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24708 ce2b1a6d-e550-0410-aec6-3dcde31c8c00