[Bug 56185] The GitLab Windows test job runs even when not needed

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=56185

--- Comment #3 from Rémi Bernon  ---
Fwiw it's probably the only way to do it with Gitlab pipelines, and I can live
with it, but maybe we could have the child pipeline be used only as a "Windows
tests" job, and not replace the individual and direct build-linux / build-mac /
test-linux* (and eventual? test-mac*) jobs.