Bug 33608: (QA follow-up) Restore older gt zero tests

Bug 33608: (QA follow-up) Restore older gt zero tests

See the Bugzilla report. I have been asked to restore the former
tests although I definitely think that they are wrong. Will address
that on bug 34308 separately.

This currently has the side-effect of negative lost values being
interpreted as 'found'. (Do not use negative lost values!)
The added subtest still reflects that now. Added a few TODOs.

Test plan:
[1] Prove t/db_dependent/Koha/Items.t

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>