tests: acpi: rename test_acpi_tables()/test_dst_table() to reflect its usage

Main purpose of test_dst_table() is loading a table from QEMU
with checking that checksum in header matches actual one,
rename it reflect main action it performs.

Likewise test_acpi_tables() name is to broad, while the function
only loads tables referenced by RSDT, rename it to reflect it.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
