feat(ngRepeat): expose the iterating properties over the alias

Expose the properties `$index`, `$first`, `$middle`, `$last`, `$odd` and `$even` as part of the alias

Closes #9582
you know, if there's no aliasAs expression, and we aren't going to expose this object, why not just declare the object outside of the closure, so that we don't keep re-creating it?