when an existing accessor is redefined (a configurable accessor can
potentially be redefined as a non-configurable (i.e., DONT_DELETE)).


Review URL: http://codereview.chromium.org/556040

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3719 ce2b1a6d-e550-0410-aec6-3dcde31c8c00