bug#56683: 29.0.50; long lines fix doesn't work correctly when lines are truncated

[Eli Zaretskii]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: Gregory Heytings <gregory@heytings.org>,  andreyorst@gmail.com,
>   56683@debbugs.gnu.org
> Date: Fri, 22 Jul 2022 08:53:33 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Gerd, any ideas or comments?
> 
> Forgot one thing:  There seem to be a place in dispextern.h where
> last_visible_x is set to the number 1000000.  That's odd.

That's a different kind of "infinity" ;-)