8272461: G1: remove empty declaration of cleanup_after_scan_heap_roots

Reviewed-by: kbarrett

src/hotspot/share/gc/g1/g1RemSet.hpp

@@ -107,8 +107,7 @@ class G1RemSet: public CHeapObj<mtGC> {
   // Prepare for and cleanup after scanning the heap roots. Must be called
   // once before and after in sequential code.
   void prepare_for_scan_heap_roots();
-  // Cleans the card table from temporary duplicate detection information.
-  void cleanup_after_scan_heap_roots();
+
   // Print coarsening stats.
   void print_coarsen_stats();
   // Creates a gang task for cleaining up temporary data structures and the