8322888: Parallel: Remove unused variables in PSPromotionManager

Reviewed-by: kbarrett

Author: albertnetymk

src/hotspot/share/gc/parallel/psPromotionManager.cpp

@@ -173,13 +173,9 @@ void PSPromotionManager::reset_stats() {
 #endif // TASKQUEUE_STATS
 
 PSPromotionManager::PSPromotionManager() {
-  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
-
   // We set the old lab's start array.
   _old_lab.set_start_array(old_gen()->start_array());
 
-  uint queue_size = claimed_stack_depth()->max_elems();
-
   if (ParallelGCThreads == 1) {
     _target_stack_size = 0;
   } else {