Shenandoah: Remove unused fields in init mark tasks

There are unused fields in ShenandoahInitMarkRootsTask and ShenandoahInitTraversalCollectionTask.

diff -r 98fe04cf4e13 src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.cpp Tue Feb 25 12:01:35 2020 -0500
+++ b/src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.cpp Wed Mar 11 19:47:50 2020 -0400
@@ -84,12 +84,10 @@
 class ShenandoahInitMarkRootsTask : public AbstractGangTask {
 private:
   ShenandoahAllRootScanner* _rp;
- bool _process_refs;
 public:
- ShenandoahInitMarkRootsTask(ShenandoahAllRootScanner* rp, bool process_refs) :
+ ShenandoahInitMarkRootsTask(ShenandoahAllRootScanner* rp) :
     AbstractGangTask("Shenandoah init mark roots task"),
- _rp(rp),
- _process_refs(process_refs) {
+ _rp(rp) {
   }
 
   void work(uint worker_id) {
@@ -292,12 +290,12 @@
   task_queues()->reserve(nworkers);
 
   if (heap->has_forwarded_objects()) {
- ShenandoahInitMarkRootsTask<RESOLVE> mark_roots(&root_proc, _heap->process_references());
+ ShenandoahInitMarkRootsTask<RESOLVE> mark_roots(&root_proc);
     workers->run_task(&mark_roots);
   } else {
     // No need to update references, which means the heap is stable.
     // Can save time not walking through forwarding pointers.
- ShenandoahInitMarkRootsTask<NONE> mark_roots(&root_proc, _heap->process_references());
+ ShenandoahInitMarkRootsTask<NONE> mark_roots(&root_proc);
     workers->run_task(&mark_roots);
   }
 
diff -r 98fe04cf4e13 src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp Tue Feb 25 12:01:35 2020 -0500
+++ b/src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp Wed Mar 11 19:47:50 2020 -0400
@@ -162,8 +162,6 @@
 private:
   ShenandoahCSetRootScanner* _rp;
   ShenandoahHeap* _heap;
- ShenandoahCsetCodeRootsIterator* _cset_coderoots;
- ShenandoahStringDedupRoots _dedup_roots;
 
 public:
   ShenandoahInitTraversalCollectionTask(ShenandoahCSetRootScanner* rp) :