Get rid of hack for freezing time on AR tests

We can now make use of the existent #travel/#travel_to helper methods
added to AS test case and available in all tests.
[ci skip] added after_touch callback documentation

[ci skip] added more explanation for `after_touch` callback
Merge pull request #13032 from kuldeepaggarwal/after_touch_documentation

[ci skip] added after_touch callback documentation [ci skip]