8280079: Serial: Remove empty Generation::prepare_for_verify

Reviewed-by: tschatzl, iwalulya

src/hotspot/share/gc/serial/tenuredGeneration.cpp

@@ -212,9 +212,6 @@ void TenuredGeneration::assert_correct_size_change_locking() {
   assert_locked_or_safepoint(ExpandHeap_lock);
 }
 
-// Currently nothing to do.
-void TenuredGeneration::prepare_for_verify() {}
-
 void TenuredGeneration::object_iterate(ObjectClosure* blk) {
   _the_space->object_iterate(blk);
 }

src/hotspot/share/gc/serial/tenuredGeneration.hpp

@@ -97,8 +97,6 @@ class TenuredGeneration: public CardGeneration {
 
   HeapWord* expand_and_allocate(size_t size, bool is_tlab);
 
-  virtual void prepare_for_verify();
-
   virtual void gc_prologue(bool full);
   virtual void gc_epilogue(bool full);
 

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

@@ -301,9 +301,6 @@ void CardGeneration::compute_new_size() {
   }
 }
 
-// Currently nothing to do.
-void CardGeneration::prepare_for_verify() {}
-
 void CardGeneration::space_iterate(SpaceClosure* blk,
                                                  bool usedOnly) {
   blk->do_space(space());

src/hotspot/share/gc/shared/cardGeneration.hpp

@@ -73,8 +73,6 @@ class CardGeneration: public Generation {
 
   virtual void invalidate_remembered_set();
 
-  virtual void prepare_for_verify();
-
   // Grow generation with specified size (returns false if unable to grow)
   bool grow_by(size_t bytes);
   // Grow generation to reserved size.

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

@@ -1045,16 +1045,8 @@ void GenCollectedHeap::release_scratch() {
   _old_gen->reset_scratch();
 }
 
-class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
-  void do_generation(Generation* gen) {
-    gen->prepare_for_verify();
-  }
-};
-
 void GenCollectedHeap::prepare_for_verify() {
   ensure_parsability(false);        // no need to retire TLABs
-  GenPrepareForVerifyClosure blk;
-  generation_iterate(&blk, false);
 }
 
 void GenCollectedHeap::generation_iterate(GenClosure* cl,

src/hotspot/share/gc/shared/generation.hpp

@@ -364,10 +364,6 @@ class Generation: public CHeapObj<mtGC> {
   virtual void post_compact() { ShouldNotReachHere(); }
 #endif
 
-  // Some generations may require some cleanup actions before allowing
-  // a verification.
-  virtual void prepare_for_verify() {}
-
   // Accessing "marks".
 
   // This function gives a generation a chance to note a point between