s390x: Interception tests

Certain CPU instructions will cause an exit of the virtual
machine. Run some of these instructions to check whether
they are emulated right by KVM (or QEMU).

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>