fix(ngRepeat): do not sort object keys alphabetically

BREAKING CHANGE:

Previously, the order of object properties was consistent and simple. Now, it's not guaranteed to
be any particular order at all.

The best approach is to convert Objects into Arrays by a filter such as https://github.com/petebacondarwin/angular-toArrayFilter
or some other mechanism, and then sort them manually in the order you need.

Closes #6210