selftests: KVM: testing the local IRQs resets

Local IRQs are reset by a normal cpu reset.  The initial cpu reset and
the clear cpu reset, as superset of the normal reset, both clear the
IRQs too.

Let's inject an interrupt to a vCPU before calling a reset and see if
it is gone after the reset.

We choose to inject only an emergency interrupt at this point and can
extend the test to other types of IRQs later.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
[minor fixups]
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20200131100205.74720-7-frankja@linux.ibm.com


Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>