All uses of %AddProperty are replaced by %SetProperty.  A few uses of
IgnoreAttributesAndSetLocalProperty are added, and the runtime version
of it adds a PropertyAttributes argument.  Only the JSObject class
in objects.cc now uses AddProperty, and it can become private.

Review URL: http://codereview.chromium.org/6445

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@426 ce2b1a6d-e550-0410-aec6-3dcde31c8c00