Revert "Bug 9828 : Followup for Queryparser and deletion of useless 6XX$9"

This reverts commit 49788987b29f14884a59d41602c7821fec03e491.
Revert "ug 9828 : Add and fix comments in UNIMARC biblio-koha-indexdefs.xml"

This reverts commit 5bbe42932e6395a8cb49c880c094c21b40590fd3.
Revert "Bug 9828: More specific indexing of UNIMARC 6XX fields"

This reverts commit 0dd1ac40a0df984bee6583f13f80744b539b8f37.
Bug 13088: (RM followup) add missing pref mock

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>