bug#61704: 29.0.60; Crash in get_narrowed_begv

[Eli Zaretskii]

> Date: Wed, 22 Feb 2023 20:20:02 +0800
> From:  Po Lu via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> The cause is an arithmetic trap in get_narrowed_begv:
> 
>   return max ((pos / len - 1) * len, BEGV);
> 
> where len is 0.  The window was previously being resized, and has a
> pixel width of 24.

How do you get such windows?  I thought we never allowed windows that
are so small.

Anyway, I installed a possible fix on the emacs-29 branch, please see
if it solves this.