bug#51110: Native-comp leaks fds open on /dev/ptmx

[Eli Zaretskii]

> From: Stephen Gildea <stepheng+emacs@gildea.com>
> Date: Sat, 09 Oct 2021 08:45:25 -0700
> 
> src/emacs -Q --eval '(setq invocation-name "emacs-leaks")' --eval 
> '(mh-version)'

What real-life use case requires you to modify invocation-name?  That
variable is supposed to be read-only: it tells the program name used
to invoke Emacs of the running session.  If you change it, other
features will become confused.

IOW, I don't think we want to support this kind of usage.