bpo-36511: clean up python process before deploy

[paulmon]

If the previous buildbot test times out, there will be orphaned python processes that prevent deploy from working. Kill python.exe processes before trying to clean remote test directory

@zooba @zware

https://bugs.python.org/issue36511

[zware]

LGTM, provided that the kill command exists :). I may be operating from out of date information, but I thought Windows only offered taskkill /IM python.exe?

[zooba]

Agreed with Zachary - "kill" isn't a Windows cmd.exe command (it is an alias in PowerShell), and I'm pretty sure you've only got cmd.exe commands at the other end of the SSH connection (since dir /b won't work in PowerShell).

Unless it's a new/extra addition on the buildbot?

[paulmon]

kill.exe is a command on Windows IoT Core which is what the buildbot is running.
There is no taskkill.exe on Windows IoT Core.
I haven't seen this problem occur since I made this PR.
The last time the arm32 worker machine was producing bad results (stack overflow test kept failing)
because it was unhealthy a reboot was required to recover it.

[zware]

Ok, we'll give this a try then.