bug#68244: hash-table improvements

[Eli Zaretskii]

> From: Andy Moreton <andrewjmoreton@gmail.com>
> Date: Sat, 20 Jan 2024 20:20:57 +0000
> 
> I can no longer reproduce the problems on master or on emacs-29 with
> ENABLE_CHECKING.

OK, thanks.

> I still get a few backtraces repeatably when bootstrapping a native
> build on the emacs-28 branch, but I suspect that is not of much interest
> any more.

Right.  If you want to be able to compile that branch anyway, my
suggestion is to lower native-comp-speed to 1.