Incidentally, this is the first time I’m running
that test on bare metal rather than in a Debian VM
(hence a few oddities previously).

This is not the cleanest of approaches, but it
does get the job done (and obviates the need for
36b38160).

It's apparently not possible to completely disable update checking in
TB78, so try and delay it as far as possible as a workaround for the
moment.  I get about a 6 minutes respite here, which could be enough.

The issue is that the popup announcing the update messes with input
focus, and can break tests unexpectedly.

When no language pack is detected (i.e. when not
using the distro’s package), the Languages manager
doesn’t exist.

Merge branch 'vv/thunderbird78' of https://salsa.debian.org/hypra-team/regression-testing into vv/thunderbird78

Merge branch 'vv/thunderbird78' of https://salsa.debian.org/hypra-team/regression-testing into vv/thunderbird78

When running a debug session, it can be useful to locate the actual
focus, so make this function available so it can be used that way.

Merge branch 'vv/thunderbird78' of https://salsa.debian.org/hypra-team/regression-testing into vv/thunderbird78

Merge branch 'vv/thunderbird78' of https://salsa.debian.org/hypra-team/regression-testing into vv/thunderbird78

This allows specific timeouts for cases where a window is known to be
slow to appear, or where it is expected for the window to pop up after
a delay.

Merge branch 'vv/thunderbird78' of https://salsa.debian.org/hypra-team/regression-testing into vv/thunderbird78

ast.Constant is new in 3.9, so use the older deprecated API that works
in 3.7.