To change to the old behavior, pass --quiet. The aim is to be make it easier to debug issues only reproducing in the CI. https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1289
And add the necessary glue so those initialize a X11 clutter backend. This should get Clutter tests that are dependent on windowing to work again, thus they were enabled back again. https://gitlab.gnome.org/GNOME/mutter/merge_requests/672
Clutter doesn't hold anymore backend implementations, move tests where we have one that we may assign. https://gitlab.gnome.org/GNOME/mutter/merge_requests/672