tests/qtest/bios-tables-test.c: Remove the fall back path

tests/qtest/bios-tables-test.c: Remove the fall back path

The expected ACPI AML files are moved now under ${arch}/{machine} path.
Hence, there is no need to search in old path which didn't have ${arch}.
Remove the code which searches for the expected AML files under old path
as well.

Suggested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20240716144306.2432257-7-sunilvl@ventanamicro.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>