test-compat: merge mercurial-4.7 into mercurial-4.6

--HG--
branch : mercurial-4.6
4 jobs for topic/mercurial-4.6/release-prep in 3 minutes and 31 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed doc #200930

00:00:25

manual pytype #200927
allowed to fail manual
passed tests-py2-cext #200928

00:03:31

passed tests-py2-pure #200929

00:03:13