Bug 1893677 - Stop making some automation tiers print their own BUILDSTATUS. r=firefox-build-system-reviewers,ahochheiden

Some automation tiers ultimately end up calling normal tiers, which
will print their own BUILDSTATUS already. This kind of didn't cause
problems before bug 1859011 presumably because of buffering of the
automation tier output, but is now causing problems because the tier
monitor doesn't want to see a tier start multiple times.

Also, now that bug 1859011 made automation tiers buffered by command
rather than by target, we don't need the hack with automation-start,
simplifying the setup.

Differential Revision: https://phabricator.services.mozilla.com/D209095