AnyPS5 never suspends the running title: sceSystemServiceGetStatus never
reports background execution and sceSystemServiceReceiveEvent has no
event to deliver. Enabling or disabling the suspend notification, and
blocking or unblocking a suspend, therefore change nothing and return
success. The sceSystemService notification calls forward to their
sceLncUtil twins.
A null reason and an unblock with no block left throw, since the
console's answers to them are not measured.
The new guest_system_service_status tests check each answer.
