8240722: [BACKOUT] G1DirtyCardQueue destructor has useless flush

Backout JDK-8240133

Reviewed-by: sjohanss

src/hotspot/share/gc/g1/g1DirtyCardQueue.cpp

@@ -50,6 +50,10 @@ G1DirtyCardQueue::G1DirtyCardQueue(G1DirtyCardQueueSet* qset) :
   PtrQueue(qset, true /* active */)
 { }
 
+G1DirtyCardQueue::~G1DirtyCardQueue() {
+  flush();
+}
+
 void G1DirtyCardQueue::handle_completed_buffer() {
   assert(_buf != NULL, "precondition");
   BufferNode* node = BufferNode::make_node_from_buffer(_buf, index());

src/hotspot/share/gc/g1/g1DirtyCardQueue.hpp

@@ -44,6 +44,10 @@ protected:
 public:
   G1DirtyCardQueue(G1DirtyCardQueueSet* qset);
 
+  // Flush before destroying; queue may be used to capture pending work while
+  // doing something else, with auto-flush on completion.
+  ~G1DirtyCardQueue();
+
   // Process queue entries and release resources.
   void flush() { flush_impl(); }