bug#56682: Fix the long lines font locking related slowdowns

[Gerd Möllmann]

Eli Zaretskii <eliz@gnu.org> writes:

>> Font-lock Scroll-bar Composition Output
>> ------------------------------------------------------------
>> on     on         on          GCs: 14 Elapsed time: 7.276626 seconds
>> on     off        on          GCs: 1 Elapsed time: 5.363002 seconds
>> on     off        off         GCs: 1 Elapsed time: 3.967520 seconds
>
> Thanks.  How about now, after I installed the last change?

Font-lock Scroll-bar Composition Output
------------------------------------------------------------
on        on         on          GCs: 16 Elapsed time: 5.496764 seconds
on        off        on          GCs: 1 Elapsed time: 5.362916 seconds
on        off        off         GCs: 1 Elapsed time: 3.947306 seconds

That's with
280b8c96cc origin/feature/long-lines-and-font-locking Improve display of 
columns on mode-lin