Replies to outdated code comments should also be outdated (#13217)

Replies to outdated code comments should also be outdated (#13217)

* When replying to an outdated comment it should not appear on the files page

This happened because the comment took the latest commitID as its base instead of the
reviewID that it was replying to.

There was also no way of creating an already outdated comment - and a
reply to a review on an outdated line should be outdated.

Signed-off-by: Andrew Thornton <art27@cantab.net>
* fix test

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>