tests/acpi: add test case for VIOT

Add two test cases for VIOT, one on the q35 machine and the other on
virt. To test complex topologies the q35 test has two PCIe buses that
bypass the IOMMU (and are therefore not described by VIOT), and two
buses that are translated by virtio-iommu.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Message-id: 20211210170415.583179-7-jean-philippe@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>