Python testing - add a way to force reboot the app

[cecille]

Reproduction steps / Feature

yaml pipes this though a pseudo command, not sure what catches that on the back end. We should plumb something similar through python.

Platform

python

Platform Version(s)

No response

Type

Manually tested with SDK

(Optional) If manually tested please explain why this is only manually tested

No response

Anything else?

No response

[cecille]

See #35712 (comment)

Will need to look more into how this is done - it must be something triggered through the app, because we can't assume the app is even running. Though we DO have an app pid. It just makes things complicated with the named pipe commands to bring things down and back up. Yaml doesn't have that facility, so getting both working together can be a bit tricky.