Add unit test local cpu guide and enable base testcase (#1566)

### What this PR does / why we need it?
Use Base test and cleanup all manaul patch code
- Cleanup EPLB config to avoid tmp test file
- Use BaseTest with global cache
- Add license
- Add a doc to setup unit test in local env 

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
CI passed

Signed-off-by: Yikun Jiang <yikunkero@gmail.com>

tests/ut/test_ascend_config.py

@@ -1,17 +1,32 @@
+#
+# 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.
+# This file is a part of the vllm-ascend project.
+#
+
 import os
-import unittest
 from unittest import mock
 
 from transformers import PretrainedConfig
 from vllm.config import ModelConfig, VllmConfig
 
+from tests.ut.base import TestBase
 from vllm_ascend.ascend_config import (_check_torchair_supported,
                                        check_ascend_config,
                                        clear_ascend_config, get_ascend_config,
                                        init_ascend_config)
 
 
-class TestAscendConfig(unittest.TestCase):
+class TestAscendConfig(TestBase):
 
     @staticmethod
     def _clean_up_ascend_config(func):