Trigger emergency shutdown on resume when the boot device is missing
i.e. it was removed during suspend. The idea is that when suspended, both sequences of user actions should result in emergency shutdown:
- wake up the system, then unplug the boot device: this works
- unplug the boot device, then wake up the system: this used to work but the fix for #11729 (closed) broke it as a side effect (e4e7f812)
See #11052 (comment 64086) and follow-ups.