heptapod-ci: also run some test for chg

I am not are of any regular effort to run test with chg. So let's at least do it
here.

Differential Revision: https://phab.mercurial-scm.org/D8178
11 jobs for topic/stable/chg-test in 103 minutes and 48 seconds (queued for 1 minute and 57 seconds)