[BUGFIX] Indexed search broken after moving "SearchResultContentObject"

Indexed search still uses the old cobject in both
plugins.

The problem arieses in just to call one method from
SearchResultContentObject->register_and_explode_search_string()

The necessary functions are moved to the common
IndexedSearchUtility.

Resolves: #64716
Releases: master
Change-Id: I386330f1f66342ee838e3616cac7f0924bd31522
Reviewed-on: http://review.typo3.org/36566


Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>