tests: add support to test against OpenSSH for Windows #3290
Since it has been waiting for this long, I think it won't harm much if we take it the safe route and wait with the merge until after Wednesday. There's so little time left I figure it might not be worth rocking the boat now... I'm not sure how to estimate how safe/risky this change is so I rather we play it safe.
Testing against OpenSSH for Windows requires v22.214.171.124 or newer due to the use of AllowUsers and DenyUsers. For more info see: https://github.com/PowerShell/Win32-OpenSSH/wiki/sshd_config