Implementing __defineSetter__ and __defineGetter__ with an array index as argument as described in issue 242. For performance reasons, the change is not applied to arrays. This conforms to the behavior of Safari.
Review URL: http://codereview.chromium.org/46030

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1507 ce2b1a6d-e550-0410-aec6-3dcde31c8c00