Bug 21610: Add tests

Bug 21610: Add tests

Adding few tests to Koha/Object.t in order to highlight what we are
trying to fix.

Note that Koha::ItemType->store was wrong for notforloan, the default
value should be null
    `notforloan` smallint(6) DEFAULT NULL,
but the previous fix (bug 21599) made it default to '0'

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 9330deee558f553c357edf8eb1aa96bd40563087)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>