[3.12] gh-109594: Fix concurrent.futures test_timeout() (GH-110018) (#110021)

gh-109594: Fix concurrent.futures test_timeout() (GH-110018)

Fix test_timeout() of test_concurrent_futures.test_wait. Remove the
future which may or may not complete depending if it takes longer
than the timeout ot not. Keep the second future which does not
complete before wait(). Make also the test faster: 0.5 second instead
of 6 seconds, so remove @support.requires_resource('walltime')
decorator.
(cherry picked from commit 9be283e5e15d5d5685b78a38eb132501f7f3febb)

Co-authored-by: Victor Stinner <vstinner@python.org>