replace paddle.fluid.layers.selu with paddle.nn.functional.selu

* Remove API: gather
	replace the paddle.fluid.layers.gather with paddle.gather

* modify the call of gather from old style to new style

remove pad_constant_like which is not used in paddle 2.0

* remove unstack in nn.py under fluid

* remove unstack under fluid

* clean fluid elementwise_pow, remove API

* clean elem_pow doc

* clean elementwise_mod

* clean elementwise min, floordiv, mod

* remove swish in nn.py under fluid

* fix tswish test case

* remove chunk_eval

* [CodeStyle][py2][U004] unecessary explicit `object` inheritance in class definition

* fix an increment

* move fluid.layers.deformable_conv to static.nn

* modify example code

* fix doc

* Update common.py
Co-authored-by: NLigoml <39876205+Ligoml@users.noreply.github.com>

* [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)`

* standard_api

* add hardtanh

* [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

* standard api

* fix ci bugs

* fix ci bugs

* fix ce bugs

* fix typo `Fasle`/`Flase` -> `Flase`

* fix typo `Ture` -> `True`

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* rename op in yaml

* fix test_layout_autotune

* fix layout autotune of transpose

* [Zero-Dim] support input 0D Tensor for unary api

* fix CI

* [CodeStyle] remove all future import

* revert test_error.py

* restore future import in example code

* move_merge_selected_rows

* update code

* polish code comments

* polish data_device_transform.cc

* trim trailing whitespace

* fix `.cmake-format.py`

* revert npu ut changes, avoid npu ci error

Adapt tensor output_size for conv2d_transpose and depthwise_conv2d_transpose

[Eager, Performance optimization] reduce_all interface move reduce_all flag from python to C++ (#45744)

* [Eager, Performance optimization] move reduce_all flag from python to c++

* polish reduce_all

* fix ci error

* fix errors

* [Eager, Performance optimization] reduce_max / min polish

* polish reduce_max / min

* update min/max kernel reduce_all logic

* fix a mistake

* fix ci errors

* fix errors

* [Eager] fix pool2d interface under eager mode

* add use_gpudnn for pool2d

* fix pool2d yaml conflicts

* fix pool2d yaml

* [Eager] fix spectral_norm interface under eager mode

* fix spectral_norm yaml config

* fix split bug

* solve function redefine

* fix fluid.layers.split and add unit test

* delete splitInferMeta register in unary.cc

* modify test_split_op GPU unit test

* modify test_split_op GPU unit test place param

* refactor split op and fix infershape bugs

* add () in && and ||

* fix split C++ unit test

* fix split infershape