fix bug (#42314)

paddle/fluid/distributed/ps/table/memory_sparse_table.h

@@ -94,9 +94,9 @@ class MemorySparseTable : public Table {
 
  protected:
   const int _task_pool_size = 24;
-  size_t _avg_local_shard_num;
-  size_t _real_local_shard_num;
-  size_t _sparse_table_shard_num;
+  int _avg_local_shard_num;
+  int _real_local_shard_num;
+  int _sparse_table_shard_num;
   std::vector<std::shared_ptr<::ThreadPool>> _shards_task_pool;
   std::unique_ptr<shard_type[]> _local_shards;
 };