test_loop_tick_witness_arms_over_tcp_on_windows swapped the module's `os`
binding for a proxy reporting name="nt" so a Linux interpreter would take
the non-POSIX branch. That is the "Don't fake the host OS" case: the test
only passes if the interpreter believes it is on another OS. Mark it
windows_only so the tests-os lane runs it on windows-latest for real;
scripts/ci/list_os_marked_tests.py picks the file up by marker name and
it is skipped (not errored) on Linux/macOS. The create=True tripwire from
the earlier salvage commit is what makes it runnable there.
teknium1
df8b548797