Bug 21912: Add tests for Koha::Objects->search

Bug 21912: Add tests for Koha::Objects->search

This patch adds simple tests for the current behaviour. Specifically the
return values in both scalar and list context.

To test:
- Apply this patch
- Run:
  $ prove t/db_dependent/Koha/Objects.t
=> SUCCESS: Tests pass
- Sign off :-D

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 7669697732e3abf3b2c5a32446115d277be7342e)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>