manager should tear down if a switch goes offline

[timsnyder-siv]

@sagark, is it a "feature" that the manager continues waiting if a switch is found to be not running? I would expect that you would want the manager to tear things down and treat the simulation as if it failed but maybe this happens sometimes and you typically ssh to the host and restart the switch to keep things going?

I don't think it was purposeful, I probably did it this way for debugging and then didn't fix it. I think it would make sense to have the manager teardown everything if a switch goes down in a future PR.

Originally posted by @sagark in https://github.com/firesim/firesim/issues/986#issuecomment-1090608797