This is the only "language" from the list whose name is special and
should be localized at runtime, yet before we set any Preferences
language. It needs to be localized as the System Language itself which
will be run-dependant.
For instance, if your system is in French, it will be displayed as
"Langue système" but if you change your system to Korean, at next run,
it would show "시스템 언어". It is a per-run localization, independant
from the language selected in Preferences, and even less dependant from
build-time system language.
We were skipping tests when there is no display, which is always the
case on Windows. However, these tests always showed as succeeded.
Unless you looked at the test log, you wouldn't noticed that most of
the tests weren't actually performed.
Exit these tests with the value GIMP_EXIT_TEST_SKIPPED instead of
EXIT_SUCCESS.
