bug#31492: 26.1; query-replace-regexp undo fails in regexps w/o printable chars

[Eli Zaretskii]

> From: Tino Calancha <tino.calancha@gmail.com>
> Cc: 31492@debbugs.gnu.org
> Date: Mon, 21 May 2018 10:51:43 +0900
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> 
> >> we can use the first patch; the one with the test:
> >> (/= (match-beginning 0) (match-end 0))
> >
> > No, I like the 2nd one better.
> Following patch is equivalent to the 2nd and its 1-liner
> (excluded clarification comments):

Thanks, LGTM.  If no comments emerge in a couple of days, please push.