patch 9.0.1979: Cirrus CI disabled

patch 9.0.1979: Cirrus CI disabled

Problem:  Cirrus CI disabled
Solution: re-enable Cirrus CI

Ref patch 9.0.1912:

> Perhaps at the beginning of the next month we can revisit and enable
> just a build without testing it.  Hopefully this is won't take too
> many credits and we can at least verify that building works.

Actually enabling testing should be fine. In the last month there were
three Cirrus CI jobs and credits ran out on Sep 15, but now there is
only one Cirrus CI job, so credits shouldn't run out.

closes: #13261

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>