bug#50096: args-out-of-range in redisplay_internal

[Eli Zaretskii]

> Date: Wed, 18 Aug 2021 20:01:52 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 50096@debbugs.gnu.org
> 
> > It's 100% reproducible for me, but I'm not sure how easy would be
> > to create a test case for "emacs -Q".
> 
> I'd appreciate if you could try.

Or at least show how you arrange for auto-hscroll in the mini-window.