Run mochitest-browser-chrome, mochitest-chrome, mochitest-devtools-chrome,
mochitest-plain, and xpcshell tests against artifact builds to catch
perma-failures before they accumulate.
On Linux and Windows, these jobs run on mozilla-central and backstop pushes
on autoland. On macOS, they are try-only to preserve limited machine
capacity.
Differential Revision: https://phabricator.services.mozilla.com/D292438