bug#64800: [PATCH] Fix unstable Proced Refine Tests

[Eli Zaretskii]

> From: Laurence Warne <laurencewarne@gmail.com>
> Date: Sun, 23 Jul 2023 11:00:08 +0100
> 
> * test/lisp/proced-tests.el (proced-refine-test)
> (proced-refine-with-update-test): Refine on session id (sess) rather
> than process id (pid) as the refiner for pid keeps processes with
> a parent process id equal to the pid refined on, which lead to
> intermittent test failures as the refine tests checked pids matched
> the pid refined on for all remaining processes.

When I run "M-x proced", I don't see "Sess" on the heading.  I do see
PID, of course.

To remind you: we selected PID because it's portable: it exists in the
Proced display on every supported platform.

Thanks.