Fix skipped windows integration tests

There's arguably a bug in the way that powershell's [int] operator converts floats to ints. Specifically, [int](4.5) == 4 but [int]4.5000000001 == 5. I'd expect (reasonably I think) for int to have either floor or proper round semantics.

Anyway, the result of this bug was that some windows integration tests (possibly other tests too) were being silenty no run. This is because there are currently 27 integration tests, and with the fixed 6 test units (i.e. CI_NODE_TOTAL), (27/6) == 4.5, but [int]4.5 == 4. So the last three integration tests were being silently dropped.

This change fixes the above problem, but it turns out that some of the tests that were being dropped fail reliably! I've added those test to the list of expected failures here, but this is intended to be a temporary solution to unblock other MRs. We should investigate why these test are failing and if possible fix them.

Note that while the two test in question fail in all 4 windows environments (1809, 2004, 20H2, 21H1), I've only added them to the 1809 list of expected failures. This is because it appears that the check windows xxxx integration test failures jobs don't even run! I'll not add the two test to the expected failures for the other three environments so we can more easily tell when they do run (because they should fail).