Just like the previous tests, boots a Linux kernel on a aarch64 target
using the virt machine.

One special option added is the CPU type, given that the kernel
selected fails to boot on the virt machine's default CPU (cortex-a15).

Signed-off-by: Cleber Rosa <crosa@redhat.com>
Reviewed-by: Caio Carrara <ccarrara@redhat.com>
Message-Id: <20190312171824.5134-18-crosa@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>