8277221: G1: Remove methods without implementations in G1CollectedHeap

Reviewed-by: tschatzl

src/hotspot/share/gc/g1/g1CollectedHeap.hpp

@@ -777,8 +777,6 @@ class G1CollectedHeap : public CollectedHeap {
   // Start a concurrent cycle.
   void start_concurrent_cycle(bool concurrent_operation_is_full_mark);
 
-  void wait_for_root_region_scanning();
-
   void prepare_tlabs_for_mutator();
 
   void retire_tlabs();
@@ -936,9 +934,6 @@ class G1CollectedHeap : public CollectedHeap {
 
   void fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) override;
 
-  // Try to minimize the remembered set.
-  void scrub_rem_set();
-
   // Apply the given closure on all cards in the Hot Card Cache, emptying it.
   void iterate_hcc_closure(G1CardTableEntryClosure* cl, uint worker_id);