tests/acpi: update expected SRAT files

Update expected SRAT files for the change to account for NVDIMM NUMA
nodes in the SRAT.

AML diffs:

tests/data/acpi/pc/SRAT.dimmpxm:
Message-Id: <20200606000911.9896-4-vishal.l.verma@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

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

 /* List of comma-separated changed AML files to ignore */
-"tests/data/acpi/pc/SRAT.dimmpxm",
-"tests/data/acpi/q35/SRAT.dimmpxm",
-"tests/data/acpi/virt/SRAT.memhp",