ACPICA: Debugger: Fix possible fault with the "test objects" command

ACPICA commit 349dd29335d6928f883bc95c614a0edd033141bb

 - Fault on Field Units
 - Some restructuring
 - General cleanup of dbtest module

Link: https://github.com/acpica/acpica/commit/349dd293


Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>