KVM: selftests: aarch64: Add test for restoring active IRQs

Add a test that restores multiple IRQs in active state, it does it by
writing into ISACTIVER from the guest and using KVM ioctls. This test
tries to emulate what would happen during a live migration: restore
active IRQs.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Acked-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211109023906.1091208-18-ricarkol@google.com