The arguments property of functions, if we find an optimized frame for
the function, is always a freshly allocated object.  We never try to
find an existing arguments object.

Review URL: http://codereview.chromium.org/6349050

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6581 ce2b1a6d-e550-0410-aec6-3dcde31c8c00