Bug 27281: Add unit test for Koha::Item->get_transfers

Bug 27281: Add unit test for Koha::Item->get_transfers

In the previous patch we introduced the new get_transfers method to the
Koha::Item object. This patch adds proper unit tests for that addition.

Test plan
1/ Apply patches and confirm t/db_dependent/Koha/Item.t passes.
2/ Signoff

Signed-off-by: Petro Vashchuk <stalkernoid@gmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
JD amended patch: fix spelling reqeusted ==> requested

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>