* [CodeStyle][E711] use `is`/`is not` for comparison with `None`

* `self.assertTrue($A is None)` -> `self.assertIsNone($A)`

* `self.assertTrue($A is not None)` -> `self.assertIsNotNone($A)`

* `self.assertFalse($A is None)` -> `self.assertIsNotNone($A)`

* `self.assertEqual($A, None)` -> `self.assertIsNone($A)`

* `self.assertNotEqual($A, None)` -> `self.assertIsNotNone($A)`

* [CodeStyle][py2] remove `six` package (part2)

* six.ensure_str

* remove unused `import six`

* remove six from BUILTIN_LIKELY_MODULES

* remove six in example code

* remove some decode

* try to fix example code

* fix MockEtcdClient get/get_prefix returns data type

* fix MockEtcdClient get_prefix returns data

* fix MockEtcdClient get returns data

* remove `six` in pypi and conda requirements

* fix MockEtcdClient add_watch_callback/add_watch_prefix_callback returns data type

* refine MockEtcdClient

* fix python module not found bug

* delete unused cast,test=allcases

* test,test=ljd_test

* modify get_ut_file_map.py,test=ljd_test

* modify paddle_build.sh,test=ljd_test

* test,test=ljd_test

* update precise test logic,test=ljd_test

* it is a test,test=ljd_test

* it is a test,test=ljd_test

* it is a test,test=ljd_test

* it is a test,test=ljd_test

* it is a test,test=ljd_test

* it is a test,test=ljd_test

* precise test logic update

* [CodeStyle][black] format dy2static unittests

* format some missing files

* update lineno in test_origin_info

* update lineno in test_error

* update lineno

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* Add libpaddle.so log

* Add libpaddle.so log

* it is a test

* it is a test

* it is a test,test=coverage

* optimizing the proceess of generating ut_file_map.json

* optimizing the proceess of generating ut_file_map.json

* optimizing the proceess of generating ut_file_map.json

* optimizing the proceess of generating ut_file_map.json

* check change of unittest before checking coverage rate,test=coverage

* modify paddle_build.sh

* adding test_list.py

* it is a test for my idea,test=coverage

* it is a test,test=coverage

* it is a test,test=coverage

* optimizing coverage ci for build develop twice

* it is a test to delete a unnitest,test=coverage

* optimizing pr ci coverage

* unify  core_avx and core_noavx

* fix except error

* revert mac compile logic

* revert dylib to so

* add core_noavx branch

* remove core_noavx

* replace paddle_core by lib paddle

* polish var name

* replace paddle_core by libpaddle

* update custom device commit

* polish code by comments

* trim trailing whitespace

* fix `.cmake-format.py`

* revert npu ut changes, avoid npu ci error

* [CodeStyle] trim trailing whitespace in .md and .rst

* empty commit, test=document_fix

* add kernel dtypes check

* polish details

* fix print info, test=document_fix

* skip repeated kernel, test=document_fix

* remove test kernel, test=document_fix

* paralle_test_daily

* test=paralle_test_daily

* test=paralle_test_daily

* test=parallel_test_daily

* test=paralle_test_daily

* test=paralle_test_daily

* test=paralle_test_daily

* test=paralle_test_daily

* test=paralle_test_daily

* test=paralle_test_daily

* test=paralle_test_daily

* test=paralle_test_daily

* test pre_test_bak

* test cfs

* test_cfs,test=paralle_test_daily

* test_cfs,test=paralle_test_daily

* fix nightly test name,test=paralle_test_daily

* fix nightly test name,test=paralle_test_daily

* test ci parallel speed

* refine parallel rule,test=paralle_test_daily

* add distro zstd

* test

* test

* add pip3.8

* Revert "Revert "make inference_api_test compile with dynamic linking library (#41944)" (#43882)"

This reverts commit e6d81ddf.

* modify third_party cmake

* move SKIP_CPP_TEST return in the begining

This reverts commit f8b9073f.