Specify Python 3 in some ERTs on Mac

Specify Python 3 in some ERTs on Mac

* test/lisp/progmodes/python-tests.el
(python-tests-with-temp-buffer-with-shell): Remove setting
'python-shell-interpreter'.
(python-tests-shell-interpreter): Removed.
(python-tests-shell-interpreters): New variable.
(python-tests-with-shell-interpreter)
(python-tests-with-temp-buffer-with-shell-interpreter): New macros.
(python-tests-get-shell-interpreter): Add an optional PRED
argument to allow ERts to specify Python interpreter version.
(python-tests--get-interpreter-info): New function.
(python-tests-interpreter-3-p): New function to be used as the
PRED argument of 'python-tests-get-shell-interpreter'.
(python-shell-make-comint-1)
(python-shell-make-comint-2)
(python-shell-make-comint-4)
(python-shell-get-process-1)
(python-shell-internal-get-or-create-process-1)
(python-shell-prompt-detect-1)
(python-shell-prompt-detect-2)
(python-shell-prompt-detect-3)
(python-shell-prompt-detect-4)
(python-shell-prompt-detect-5)
(python-shell-prompt-detect-6)
(python-shell-prompt-set-calculated-regexps-6)
(python-shell-completion-at-point-jedi-completer)
(python-completion-at-point-pdb-1)
(python-completion-at-point-while-running-1)
(python-ffap-module-path-1)
(python-ffap-module-path-while-running-1)
(python-eldoc--get-doc-at-point-1)
(python-eldoc--get-doc-at-point-while-running-1)
(python-tests--run-python-selects-window)
(python-test--shell-send-block): Use the new macro.
(python-shell-completion-at-point-ipython): Remove setting
'python-tests-shell-interpreter'.
(python-shell-completion-at-point-1)
(python-completion-at-point-1)
(python-completion-at-point-2)
(python-completion-at-point-native-1)
(python-completion-at-point-native-2)
(python-completion-at-point-native-with-ffap-1)
(python-completion-at-point-native-with-eldoc-1): Use the new
macro and specify Python 3 on Mac to avoid errors.  (Bug#70815)

(cherry picked from commit bfb4c69e7f1b86e358e827f757b73161952aae3c)