message: support zend internal function.
diff: @@ -365,6 +365,13 @@ static void swoole_corountine_call_function(zend_fcall_info *fci, zend_fcall_inf
  int i;
  zend_execute_data *call, *current_ex = EG(current_execute_data);
  zend_function *func = fci_cache->function_handler;
  +
  + if (func->type == ZEND_INTERNAL_FUNCTION)
  + {
  + zend_call_function(fci, fci_cache);
  + return;
  + }
  +
  zend_object *object = (func->common.fn_flags & ZEND_ACC_STATIC) ? NULL : fci_cache->object;
  #if ZEND_MODULE_API_NO < 20160303
  zend_class_entry* origal_scope = EG(scope);
  @@ -442,7 +449,7 @@ static PHP_METHOD(swoole_coroutine_util, call_user_func)
  Z_PARAM_VARIADIC('*', fci.params, fci.param_count)
  ZEND_PARSE_PARAMETERS_END();
  - fci.retval = (execute_data->prev_execute_data->opline->result_type != IS_UNUSED) ? return_value : NULL;
  + fci.retval = return_value;
  swoole_corountine_call_function(&fci, &fci_cache, 0);
  }
  #endif
  @@ -483,7 +490,7 @@ static PHP_METHOD(swoole_coroutine_util, call_user_func_array)
  zend_fcall_info_args(&fci, params);
  - fci.retval = (execute_data->prev_execute_data->opline->result_type != IS_UNUSED) ? return_value : NULL;
  + fci.retval = return_value;
  swoole_corountine_call_function(&fci, &fci_cache, 1);
  zend_fcall_info_args_clear(&fci, 1);
  