MDEV-22871 follow-up fix: AHI corruption & leak

Commit bf3c862f
accidentally introduced two bugs.

btr_search_update_hash_ref(): Pass the correct parameter part->heap.

btr_search_sys_t::free(): Free all memory.

Thanks to Michael Widenius and Thirunarayanan Balathandayuthapani
for pointing out these bugs.

storage/innobase/btr/btr0sea.cc

@@ -740,7 +740,7 @@ btr_search_update_hash_ref(
 			mem_heap_free(heap);
 		}
 
-		ha_insert_for_fold(&part->table, heap, fold, block, rec);
+		ha_insert_for_fold(&part->table, part->heap, fold, block, rec);
 
 		MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_ADDED);
 	}

storage/innobase/include/btr0sea.h

@@ -338,8 +338,12 @@ struct btr_search_sys_t
   void free()
   {
     if (parts)
+    {
       for (ulong i= 0; i < btr_ahi_parts; ++i)
         parts[i].free();
+      ut_free(parts);
+      parts= nullptr;
+    }
   }
 };