For a closure created using native Function.prototype.bind() the most important information for the heap profiler user is bound function, receiver and arguments. This change adds shortcuts for those fields.
Review URL: https://chromiumcodereview.appspot.com/9382002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10675 ce2b1a6d-e550-0410-aec6-3dcde31c8c00