Bug 25723: Remove tests for removed method

Bug 25723: Remove tests for removed method

We removed the exception_holidays (and single_holidays) methods as part
of this patchset. As such, we should no longer test them ;)

Signed-off-by: Emma Perks <Emma.Perks2@uhb.nhs.uk>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Joonas Kylmälä <joonas.kylmala@helsinki.fi>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit 25f0d425eaa7c66953d02c5a5717b1b2abcb89a6)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>