core: Consistently use local reference to access()

Follows-up 3b53b75160.

> Our internal code always calls the local `access` reference, not `jQuery.access`. Which means if someone were to override this method, jQuery core APIs would not be affected (I guess we kept it exposed for backwards compatibility, it's not a documented API though).
> Except that core APIs **are** affected when an object is passed, because the loop calls the public one instead of the private one.

Let's call the private reference there as well?