BibIndex: regression tests fix for itemcount index

* Adds `setUp` method for `BibIndexItemCountIndexTest` to initialize the
  tests.

Signed-off-by: Grzegorz Szpura <grzegorz.szpura@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
BibIndex: fix for affected indexes tests

* Removes regression tests issues for tests concerning affected indexes.

Signed-off-by: Grzegorz Szpura <grzegorz.szpura@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>