Suppress ResourceWarning in Windows process termination tests

The tests are now functionally passing - processes are being terminated
correctly. The ResourceWarning is expected behavior when forcefully
killing processes that have spawned subprocesses.

Added @pytest.mark.filterwarnings('ignore::ResourceWarning') to the
three Windows process termination tests to suppress these warnings
since they're testing the exact scenario that causes them.

Also cleaned up debug scripts that are no longer needed.

Author: felixweinberger