With this change we follow Firefox, Safari has a slightly different approach where the property is just not there (at least according to GetOwnProperty). 
Review URL: http://codereview.chromium.org/7792054

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9093 ce2b1a6d-e550-0410-aec6-3dcde31c8c00