It was a test case in the Wayland test client directory, but it wasn't a
Wayland test client but a standalone test linking to libmutter. Since it
uses rlimit to implement certain aspects of the test, it can't be made
part of the regular unit tests, as that means any test running after
being stuck with the rlimit set, thus keep it standalone, but at least
run it as part of the test suite.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1557>
