Keep a per-display list of error traps, so we don't mix them
together, and possibly deem unintended error traps outdated.
This means init/deinit calls are now stackable, and need to
happen evenly. In order to honor this, move the MetaX11Display
error trap destrution to finalize.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3230>
We currently have a bit of a disaster area wrt X11 error handling,
with all of Cogl/Clutter/Mutter offering implementations with different
expectations and different degrees of integration with other error
handlers.
It makes more sense to have a single X11 error handling implementation
that is used in all those places. Mtk seems like the reasonable place
to have this kind of general API, so adopt the more advanced code
at src/x11.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3230>
