[3.11] gh-90867: test.support.wait_process() uses LONG_TIMEOUT (GH-99071) (GH-99098)

The test.support.wait_process() function now uses a timeout of
LONG_TIMEOUT seconds by default, instead of SHORT_TIMEOUT.  It
doesn't matter if a Python buildbot is slower, it only matters that
the process completes. The timeout should just be shorter than
"forever".

(cherry picked from commit a9a8c8712665377cfa83af4b632b0db529ec1853)

Co-authored-by: Victor Stinner <vstinner@python.org>
(cherry picked from commit f09da28768b77713566e932e912f107b6b57e8fd)