This instance will be upgraded to Heptapod 0.25.0 (final) on 2021-09-22 at 15:00 UTC+2 (a few minutes of down time)

procutil: use os.devnull if sys.stdout/err is None

According to Yuya, it's better to make `procutil.stdin/err/out` always
available.

This is a bandaid until someone suggests something better.
7 jobs for topic/default/chg-test in 34 minutes and 19 seconds (queued for 7 seconds)
latest
Status Job ID Name Coverage
  Tests
passed checks-py2 #137941

00:04:51

passed test-py2-chg #137942

00:21:57

passed test-py2-pure-chg #137943

00:23:00

passed test-py2-rust-chg #137944

00:25:16

passed test-py3-chg #137945

00:10:05

passed test-py3-pure-chg #137946

00:09:39

passed test-py3-rust-chg #137947

00:09:59