test_selectors: rename test_interrupted_retry() (since it doesn't actually
retry on EINTR).
test_selectors: make timeout-related errors report the actual elapsed timeout.
Issue #16803: Stop having test.test_importlib.abc ABCs inherit from
unittest.TestCase in prep of running tests under frozen and source
importlib.
Issue #16803: Have test.test_importlib.builtin test both frozen and
source importlib.
merge from 3.3
Issue #11161: Update the documentation for ProcessPoolExecutor to note that it will not work in the interactive shell.
Merge.
Tweak some doc wording for importlib.reload
merge
Issue #19387: explain and test the sre overlap table
Issue #16803: Move test.test_importlib.extension to use both frozen and source importlib code
Issue #19375: The site module adding a "site-python" directory to sys.path, if it exists, is now deprecated.
test_resource should not assume all attributes are available when they
are individually controlled by #ifdef statements in the extension
code.
merge
Issue13234 Allow listdir to handle extended paths on Windows (Patch by Santoso Wijaya)
Issue13234 Credit Santoso for the patch and add NEWS item
Correct whitespace in test_os
null merge
Issue #19399: fix sporadic test_subprocess failure.

Change Thread.join() with a negative timeout to just return.  The
behavior isn't documented then, but this restores previous
behavior.
Fiddled Thread.join() to be a little simpler.  Kinda ;-)