add log for FLAGS_communicator_send_wait_times

paddle/fluid/operators/distributed/communicator.cc

@@ -68,6 +68,8 @@ Communicator::Communicator(const RpcCtxMap &send_varname_to_ctx,
           << FLAGS_communicator_max_send_grad_num_before_recv;
   VLOG(0) << "communicator_thread_pool_size: "
           << FLAGS_communicator_thread_pool_size;
+  VLOG(0) << "communicator_send_wait_times: "
+          << FLAGS_communicator_send_wait_times;
   VLOG(0) << "communicator_max_merge_var_num: "
           << FLAGS_communicator_max_merge_var_num;
   VLOG(0) << "communicator_fake_rpc: " << FLAGS_communicator_fake_rpc;