Fix ClassCleanup not called when the first test in class is ignored

[Youssef1313]

When the first test of a class is ignored (and the first test ever in the assembly), we will not call AssemblyInitialize, so IsAssemblyInitializeExecuted will be false.

However, in that case, we still want to call RunClassCleanup so that the test is marked as completed (see MarkTestComplete). Not marking the ignored test as completed is problematic, because later on when all tests in the class are executed, we will still be viewing remaining tests in the class, hence we will not call class cleanup.

Note that even with this change, we respect the case where all tests in class are ignored, and we will not call ClassCleanup. The logic in ExecuteClassCleanup handles the case when class init wasn't called.

Fixes #5062

[Youssef1313]

/backport to rel/3.8

[github-actions]

Started backporting to rel/3.8: https://github.com/microsoft/testfx/actions/runs/13408191594

[Evangelink]

Suggesting a comment on the test so we don't change order without noticing impact