Bug 11891: set up tests to require that Koha::Database uses same DB handle as C4...

Bug 11891: set up tests to require that Koha::Database uses same DB handle as C4::Context

This patch removes changes in two cases to work around the fact that
Koha::Database and C4::Context were not using the same DBI database
handle.

To test:

[1] Run prove -v t/db_dependent/ILSDI_Services.t and
    prove -v t/db_dependent/Items.t.  Both tests
    should fail.
[2] Apply the main patches and run step 1 again.  This
    time, both tests should pass.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>