Remove unit tests that are no longer maintained (#22081)

python/paddle/fluid/tests/unittests/test_dist_se_resnext_async.py

-#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from __future__ import print_function
-import unittest
-from test_dist_base import TestDistBase
-
-import os
-flag_name = os.path.splitext(__file__)[0]
-
-
-class TestDistSeResneXt2x2Async(TestDistBase):
-    def _setup_config(self):
-        self._sync_mode = False
-        self._use_reader_alloc = False
-
-    @unittest.skip(reason="Skip unstable ci")
-    def test_dist_train(self):
-        self.check_with_place(
-            "dist_se_resnext.py",
-            delta=100,
-            check_error_log=True,
-            log_name=flag_name)
-
-
-if __name__ == "__main__":
-    unittest.main()