8361693: Remove Klass::clean_subklass_tree()

Reviewed-by: zgu, kbarrett

Author: Thomas Schatzl

src/hotspot/share/gc/shared/parallelCleaning.cpp

@@ -122,7 +122,7 @@ void KlassCleaningTask::work() {
 
   // One worker will clean the subklass/sibling klass tree.
   if (claim_clean_klass_tree_task()) {
-    Klass::clean_subklass_tree();
+    Klass::clean_weak_klass_links(true /* class_unloading_occurred */, false /* clean_alive_klasses */);
   }
 
   // All workers will help cleaning the classes,

src/hotspot/share/oops/klass.hpp

@@ -735,9 +735,6 @@ class Klass : public Metadata {
   void clean_subklass();
 
   static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
-  static void clean_subklass_tree() {
-    clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
-  }
 
   // Return self, except for abstract classes with exactly 1
   // implementor.  Then return the 1 concrete implementation.