[3.11] [3.12] gh-115538: Use isolate mode when running venv test_multiproces… (GH-117264) (#117265)

[3.12] gh-115538: Use isolate mode when running venv test_multiproces… (GH-117264)

[3.12] gh-115538: Use isolate mode when running venv test_multiprocessing_recursion() (GH-117116)
(cherry picked from commit 4ec347760f98b156c6a2d42ca397af6b0b6ecc50)

(cherry picked from commit ca0793980b90a6a0f9a91f1a5303a1f27b235f83)

Co-authored-by: AN Long <aisk@users.noreply.github.com>
Co-authored-by: Victor Stinner <vstinner@python.org>