8298111: Cleanups after UseMallocOnly removal

Reviewed-by: coleenp

Author: tstuefe

src/hotspot/share/memory/arena.hpp

@@ -101,8 +101,6 @@ class Arena : public CHeapObjBase {
   void* grow(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
   size_t _size_in_bytes;        // Size of arena (used for native memory tracking)
 
-  debug_only(void* malloc(size_t size);)
-
   void* internal_amalloc(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM)  {
     assert(is_aligned(x, BytesPerWord), "misaligned size");
     if (pointer_delta(_max, _hwm, 1) >= x) {
@@ -173,9 +171,6 @@ class Arena : public CHeapObjBase {
   size_t size_in_bytes() const         {  return _size_in_bytes; };
   void set_size_in_bytes(size_t size);
 
-  static void free_malloced_objects(Chunk* chunk, char* hwm, char* max, char* hwm2)  PRODUCT_RETURN;
-  static void free_all(char** start, char** end)                                     PRODUCT_RETURN;
-
 private:
   // Reset this Arena to empty, access will trigger grow if necessary
   void   reset(void) {