RFR (S) JDK-8241068: Shenandoah: improve ShenandoahTraversalGC constructor arguments

[Nilsen, Kelvin]

This starter issue is described here: https://bugs.openjdk.java.net/browse/JDK-8241068?filter=38634

The following patch addresses this issue.  I have compiled and run jtreg tests tier1, tier2, and hotspot_gc_shenandoah without regressions.

I am not authorized to directly apply this patch so will need a sponsor to apply this patch when it is judged ready to be merged.

--- old/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	2020-03-20 17:40:08.000000000 -0700
+++ new/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	2020-03-20 17:40:07.000000000 -0700
@@ -368,7 +368,7 @@
   }
 
   _traversal_gc = strcmp(ShenandoahGCMode, "traversal") == 0 ?
-                  new ShenandoahTraversalGC(this, _num_regions) :
+                  new ShenandoahTraversalGC(this) :
                   NULL;
 
   _control_thread = new ShenandoahControlThread();
--- old/src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp	2020-03-20 17:40:13.000000000 -0700
+++ new/src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp	2020-03-20 17:40:12.000000000 -0700
@@ -291,7 +291,7 @@
   }
 };
 
-ShenandoahTraversalGC::ShenandoahTraversalGC(ShenandoahHeap* heap, size_t num_regions) :
+ShenandoahTraversalGC::ShenandoahTraversalGC(ShenandoahHeap* heap) :
   _heap(heap),
   _task_queues(new ShenandoahObjToScanQueueSet(heap->max_workers())),
   _traversal_set(ShenandoahHeapRegionSet()) {
--- old/src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.hpp	2020-03-20 17:40:15.000000000 -0700
+++ new/src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.hpp	2020-03-20 17:40:15.000000000 -0700
@@ -39,7 +39,7 @@
   ShenandoahHeapRegionSet _traversal_set;
 
 public:
-  ShenandoahTraversalGC(ShenandoahHeap* heap, size_t num_regions);
+  ShenandoahTraversalGC(ShenandoahHeap* heap);
   ~ShenandoahTraversalGC();
 
   ShenandoahHeapRegionSet* traversal_set() { return &_traversal_set; }