* once smoketest is implemented in CI, will run a much smaller set of Windows module integration tests for changes to module_utils or connection subsystems
* fixes#15770
* When running under the UTF-8 codepage, Powershell subprocesses will fail (eg, Start-Job, others) if the input encoding is using the default BOM preamble. This fix forces it to use no preamble in leaf_exec and win_shell, and includes tests to verify that Start-Job works.