bug#64391: buffer narrowing slowdown regression in emacs 29

[Eli Zaretskii]

> From: Mattias Engdegård <mattias.engdegard@gmail.com>
> Date: Fri, 7 Jul 2023 13:27:12 +0200
> Cc: gregory@heytings.org,
>  acohen@ust.hk,
>  64391@debbugs.gnu.org,
>  monnier@iro.umontreal.ca
> 
> 7 juli 2023 kl. 12.27 skrev Eli Zaretskii <eliz@gnu.org>:
> 
> > I was considering applying only the first of Gregory's patches,
> > without the second.  WDYT?
> 
> I don't think that makes much sense -- the division between the two is pretty 
> much artificial.

It makes sense to me, because it minimizes changes in the code, which
at this stage in the pretest is something very important, IMO.