drop spurious declaration of splitOutReductionAndInsertSyncs

The spurious declaration was introduced in bb5e2df (Reduce number
of synchronizations produced in sequences.,
Thu Apr 19 10:03:11 2018 +0200).

Author: Sven Verdoolaege

tc/core/polyhedral/cuda/mapped_scop.h

@@ -182,8 +182,6 @@ class MappedScop {
  private:
   // Insert the optimal combination of synchronizations in the sequence
   void insertBestSyncInSeq(detail::ScheduleTree* seq);
-  // Split out reduction bands and insert reduction synchronizations.
-  void splitOutReductionsAndInsertSyncs();
   // Split out reduction member at position "dim" in "band" and
   // insert reduction synchronizations.
   void splitOutReductionAndInsertSyncs(detail::ScheduleTree* band, int dim);