tests/acpi: allow microvm test data updates.

Also add empty test data files.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20200915120909.20838-18-kraxel@redhat.com

tests/qtest/bios-tables-test-allowed-diff.h

 /* List of comma-separated changed AML files to ignore */
+"tests/data/acpi/microvm/APIC",
+"tests/data/acpi/microvm/DSDT",
+"tests/data/acpi/microvm/FACP",