x86: ioapic: Test physical and logical destination mode

This patch tests the physical destination mode by sending an
interrupt to one of the vcpus and logical destination mode by
sending an interrupt to more than one vcpus.

Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>