bug#39598: 26.3; Emacs is extremely unresponsive on a trivial python file

[Eli Zaretskii]

> From: Ivan Oreshnikov <oreshnikov.ivan@gmail.com>
> Date: Fri, 14 Feb 2020 17:08:19 +0100
> Cc: 39598@debbugs.gnu.org
> 
> Sorry, didn't notice your first message (didn't expect such a quick response 
> :).
> 
> Yes, my profile is very similar to yours:

It is.  Looks like python-nav--forward-sexp is indeed the main
culprit.  To narrow this down even more, I suggest to load python.el
(not .elc!) manually into a new Emacs session, then repeat the
experiment, and show the profile below python-nav--forward-sexp.  This
might point out the part of that function that takes the lion's share
of the run time.

Thanks.