8221361: Eliminate two-phase initialization for PtrQueueSet classes

Move allocator and CBL monitor init to constructor.

Reviewed-by: tschatzl, shade

src/hotspot/share/gc/shared/ptrQueue.hpp

@@ -303,13 +303,9 @@ protected:
   bool _all_active;
 
   // Create an empty ptr queue set.
-  PtrQueueSet();
+  PtrQueueSet(BufferNode::Allocator* allocator);
   ~PtrQueueSet();
 
-  // Because of init-order concerns, we can't pass these as constructor
-  // arguments.
-  void initialize(BufferNode::Allocator* allocator);
-
 public:
 
   // Return the associated BufferNode allocator.