8246434: Threads::print_on_error assumes that the heap has been set up

Reviewed-by: dholmes

Author: stefank

src/hotspot/share/runtime/thread.cpp

@@ -4840,8 +4840,10 @@ void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
 
-  PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
-  Universe::heap()->gc_threads_do(&print_closure);
+  if (Universe::heap() != NULL) {
+    PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
+    Universe::heap()->gc_threads_do(&print_closure);
+  }
 
   if (!found_current) {
     st->cr();