[3.7] bpo-38546: Backport multiprocessing tests fixes from master by vstinner · Pull Request #19689 · python/cpython

multiprocessing tests now call explicitly _run_finalizers() to remove
immediately temporary directories created by
multiprocessing.util.get_temp_dir().
(cherry picked from commit 039fb49)

Co-authored-by: Victor Stinner <vstinner@redhat.com>
(cherry picked from commit 632cb36)

multiprocessing tests now stop the ForkServer instance if it's
running: close the "alive" file descriptor to ask the server to stop
and then remove its UNIX address.
(cherry picked from commit 8fbeb14)

Co-authored-by: Victor Stinner <vstinner@redhat.com>
(cherry picked from commit 229f6e8)

…GH-17647)

Multiprocessing and concurrent.futures tests now stop the resource
tracker process when tests complete.

Add ResourceTracker._stop() method to
multiprocessing.resource_tracker.

Add _cleanup_tests() helper function to multiprocessing.util: share
code between multiprocessing and concurrent.futures tests.

(cherry picked from commit 9707e8e)
(cherry picked from commit 35acb35)