This reverts commit 15c87528.

* [kunlun] fix the dataloader problem in RDMA env

When running multi-machine training with Paddle DataLoader, an
unexpected segmentfault will be raised in DataLoader Process,
where the traceback goes all back to a runtime error that dataloader
workers exit unexpectedly. Similar problems have been discussed
that lead to a misbehavior of OpenCV working in multiprocessing
environment.
See
https://stackoverflow.com/questions/54013846/pytorch-dataloader-stucked-if-using-opencv-resize-method

* code style

* fix 'RuntimeError: context has already been set'

* Update dataloader_iter.py

spawn method raise error 'Can't pickle local object' in some situations

* code format check

* code style

* bump ruff to 0.0.271 and update config

* exclude third_party

* bump ruff to 0.0.272

* refine config

This reverts commit 4bcb5cc4.

* [dygraph]unify _non_static_mode() in_dygraph_mode() and in_dynamic_mode()

* [dygraph]unify _non_static_mode() in_dygraph_mode() and in_dynamic_mode()

* [dygraph]unify _non_static_mode() in_dygraph_mode() and in_dynamic_mode()

* [dygraph]unify _non_static_mode() in_dygraph_mode() and in_dynamic_mode()

* [dygraph]unify _non_static_mode() in_dygraph_mode() and in_dynamic_mode()

* [dygraph]unify _non_static_mode() in_dygraph_mode() and in_dynamic_mode()

* fixed cyclic reference that caused patial import

* fixed bad change

* fix bad import

* fix bad import

* fix bad import

* fix ut failed caused by change in_dynamic_mode

* fix ut failed caused by change in_dynamic_mode

* fixed usage of in_dynamic_mode() or in_dygraph_mode()

* revert python3 to python in .pre-commit-config.yaml

* fix merge conflicts

* move DataLoader to paddle.io. test=develop

* 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

As the title 

* add WeightedRandomSampler. test=develop

* add paddle.io.ComposeDataset & paddle.io.ChainDataset. test=develop

* init commit of new save/load

* fix failed unittests

* fix save_load_v2 unittest failed

* fix failed unittest & polish doc

* add tests for coverage

* add more tests & move static apis

* fix example code error

* polish emample code

* fix detail example code problem

* remove paddle.readers API. test=develop

* Move hapi form paddle/incubate to paddle

* Remove vision/datasets/utils.py and clean code

* Add sample code for conll05

* Print pull path when saving model

* Fix sample code after paramter_list of SGD is changed to parameters

* Fix bug in wmt16 datase

* add TensorDataset. test=develop

* add Sampler/SequenceSampler/RandomSampler. test=develop

* add IterableDataset support in multiprocess DataLoader. test=develop

* add base name alias; test=develop

* fix embedding bug; test=develop

* fix io error; test=develop

* add metric; test=develop

* add import palce; test=develop

* add setup; test=develop

* fix incubate reader; test=develop

* fix initializer error; test=develop

* add DataLoader, Dataset, BatchSampler