While the performance framework was originally written to collect
performance metrics, driving the shell by an automated script is
also useful to ensure that basic functionality is working.
Add such a basic test, initially checking top bar menus, notifications
and the overview.
Eventually it would be nice to separate the automatic scripting from
gathering performance metrics, but IMHO that can wait until we switch
from gjs' custom imports system to ES modules.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1396
