Parts of the `dbus-appinfo` test need support for converting an FD to a
path, and Hurd doesn’t currently allow that (see
https://gitlab.gnome.org/GNOME/glib/-/merge_requests/4396#note_2279923).
Since there’s no fix for that visible in the medium term (new kernel
APIs will need to be added), skip parts of the `dbus-appinfo` test which
require that functionality for now.
This prevents the whole test from failing, and means we can usefully get
results from the parts of it which don’t depend on converting FDs to
paths.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3538
