bug#70815: [PATCH] ; Enahnce python-tests.el to adapt different python interpreters

[Eli Zaretskii <eliz@gnu.org>]

> From: Mattias Engdegård <mattias.engdegard@gmail.com>
> Date: Sun, 26 May 2024 12:52:54 +0200
> Cc: Lin Sun <sunlin7.mail@gmail.com>,
>  stefankangas@gmail.com,
>  70815@debbugs.gnu.org,
>  Eli Zaretskii <eliz@gnu.org>
> 
> This change caused python-tests failures on macOS. See attached log.
> 
> On this machine which has the standard macOS Python installation, 'python' is python 2, which apparently the tests don't cope very well with. (Have you verified that they do?)
> 
> The tests pass if modified to prefer Python 3:
> 
> @@ -3722,2 +3722,2 @@ python-tests-get-shell-interpreter
> -              (cl-some #'executable-find '("python" "python3" "python2"))))))
> +              (cl-some #'executable-find '("python3" "python" "python2"))))))

I don't like this preference.  It is basically wrong, because it
second-guesses what Python is _the_ Python on the user's machine.

Let's try to find another solution.  If worse comes to worst, we could
make a change specific to macOS, but I hope we won't need to.