tests: Fix compilation when GLIB_DISABLE_DEPRECATION_WARNINGS is defined
This should fix the Coverity build, which runs with
-DGLIB_DISABLE_DEPRECATION_WARNINGS
defined in the environment (see
.gitlab-ci.yml
).
See: https://gitlab.gnome.org/GNOME/glib/-/jobs/1907625 Signed-off-by: Philip Withnall pwithnall@endlessos.org