* mv all unittests test

* fix error

* fix error

* fix

* fix

* del unittests

* fix paddle_build.sh

* fix

* fix test

* fix add test

* fix

* fix

* fix

* merge develop

* fix

* fix

* fix

* fix

* fix

* merge develop

* fix test_async_read_write

* fix test_async_read_write

* merge develop

* fix

* fix import legacy_test

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix bug

* fix

* fix coverage test bug

* fix

* fix

* fix

* fix

* fix

* fix code sstyle

* fix code

* fix code

* fix

* fix

* fix

* del test_sequence_enumerate_op.py

* fix

* autofix
Co-authored-by: NLiyulingyue <83450930+Liyulingyue@users.noreply.github.com>

* revert changes in python/paddle/distributed/fleet/utils/hybrid_parallel_util.py

* empty commit, trigger ci

* fix test_slice

---------
Co-authored-by: NSigureMo <sigure.qaq@gmail.com>

* move fc from fluid to paddle2.0

* fix unit test

* fix some examples

* fix some examples

replace cross_entropy in python/paddle/fluid/tests/unittests/test_[a-n]*.py except test_dist_transpiler.py (#48913)

* isort all files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* [CodeStyle][py2][U008] remove unnecessary args in `super()`

* remove remained args

* revert changes in test_pylayer_op

* Revert "revert changes in test_pylayer_op"

This reverts commit ff185a9ae738afac3b0264f61bde6c6b7f72e7c4.

* revert some changes in example code

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* add reducer

* refine envent for memorycopy

* add concat&split for allreduce

* apply concat & split for fuse tensor

* fix nccl dep

* fix the untest, compile problem and ddp initialize problem

* fix untest for mac & add some comments & solve the repeated param in sublayers

* fix untest for windows & fix document

* raise error if use multi-cards in fleet non_distributed mode; test=develop