8293492: ShenandoahControlThread missing from hs-err log and thread dump

Reviewed-by: phh
Backport-of: 85ec1f8d020cf2a9d7dfcc9ed75e43f0cd61c1f2

Author: shipilev

src/hotspot/share/gc/shenandoah/shenandoahControlThread.cpp

@@ -53,7 +53,7 @@ ShenandoahControlThread::ShenandoahControlThread() :
   _requested_gc_cause(GCCause::_no_cause_specified),
   _degen_point(ShenandoahGC::_degenerated_outside_cycle),
   _allocs_seen(0) {
-
+  set_name("Shenandoah Control Thread");
   reset_gc_id();
   create_and_start();
   _periodic_task.enroll();
@@ -623,16 +623,6 @@ size_t ShenandoahControlThread::get_gc_id() {
   return Atomic::load(&_gc_id);
 }
 
-void ShenandoahControlThread::print() const {
-  print_on(tty);
-}
-
-void ShenandoahControlThread::print_on(outputStream* st) const {
-  st->print("Shenandoah Concurrent Thread");
-  Thread::print_on(st);
-  st->cr();
-}
-
 void ShenandoahControlThread::start() {
   create_and_start();
 }

src/hotspot/share/gc/shenandoah/shenandoahControlThread.hpp

@@ -142,12 +142,6 @@ class ShenandoahControlThread: public ConcurrentGCThread {
   void start();
   void prepare_for_graceful_shutdown();
   bool in_graceful_shutdown();
-
-  char* name() const { return (char*)"ShenandoahControlThread";}
-
-  // Printing
-  void print_on(outputStream* st) const;
-  void print() const;
 };
 
 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHCONTROLTHREAD_HPP

src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp

@@ -1182,6 +1182,7 @@ void ShenandoahHeap::prepare_for_verify() {
 }
 
 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
+  tcl->do_thread(_control_thread);
   workers()->threads_do(tcl);
   if (_safepoint_workers != NULL) {
     _safepoint_workers->threads_do(tcl);