[Clean fluid] Clean maxout, space_to_depth, affine_channel, similarity_focus and add_position_encoding (#48410)

* Clean fluid maxout

* Clean fluid space_to_depth

* Clean fluid affine_channel and related tests

* Clean fluid similarity_focus and related tests

* Clean fluid add_position_encoding and related tests

* Fix code style

* Clean fluid resize_linear API

* Clean fluid image_resize_short API

* add image_resize back

* Clean psroi_pool and prroo_pool

* Clean roi_pool and roi_align

* delete test_trt_roi_align_op.py

* [remove fluid] under unittesets of instancenorm

* [remove fluid] under unittesets of instancenorm

* [remove fluid] under unittesets of instancenorm

* [remove fluid] under unittesets of instancenorm

* [remove fluid] under unittesets of instancenorm

* Remove API: squeeze
	Modify the funcation all of squeeze.
	Use paddle.squeeze to replace paddle.fluid.layers.squeeze

* Remove: squeeze
	fix some modifications which are not needless to the original
format

* Fix the function call of 'squeeze' from old style to new style.

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

* Modify the call of squeeze from old style to new style

* replace squeeze with paddle.squeeze

* modify the nn.py based on the review suggestion

remove a redundant comment.

* remove one comment which is not necessary

* remove crop_tensor which is not used in paddle 2.0

* replace the crop_tensor with paddle.crop in orgnizing network

* remove flatten in nn.py under fluid

* fix test case

* fix test case

* fix codestyle

* fix codestyle

* fix code style

* remove extra test case

* remove test case

* clear fluid api: warpctc, nce, identity_loss

* fix test_layers.py __init__.py

* fix loss.py

* change __init__.py and api calling method

* fix nce

* fix nce

* fix fluid.data

* delete warpctc api document

* fix loss.py

* fix ctc_loss

* fix test_warpctc_op.py

* fix test_layers.py

* fix some bug

* fix conflict

* fix ci bug

* Empty Commit test=allcase

* fix ci bug

* move conv3d

* remove unused import

* remove expand and eye under fluid.layers

* delete expand API test case

* Remove API: scatter
	replace paddle.fluid.layers.scatter with paddle.scatter

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

remove mean_iou which is not used in paddle 2.0

* Remove API: label_smooth (replace with paddle.nn.functional.label_smooth)
	Replace the paddle.fluid.layers.label_smooth with the
paddle.nn.functional.label_smooth

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

remove dice_loss which is not used in paddle 2.0

* clear fluid apis: center_loss, bpr_loss, edit_distance, hsigmoid, sampled_softmax_with_cross_entropy, rank_loss, margin_rank_loss,  sigmoid_cross_entropy_with_logits, huber_loss

* fix python/paddle/fluid/layers/loss.py

* fix test_layers.py

* fix CI bug

* fix nn.py

* remove apis in fluid.ops

* fix test_activation_nn_grad

* fix circle import error

* fix ops

* fix cos

* fix divide not inplace

* remove lazy-import part

remove crop which is not used in Paddle 2.0

* remove range

* clean fluid elementwise_pow, remove API

* clean elem_pow doc

* clean elementwise_mod

* clean elementwise min, floordiv, mod

* clean fluid elementwise_min

* fix elementwise_min op testcase

* remove chunk_eval

* remove paddle.fluid.dygraph.nn.conv2D

* fix ut

* fix conv fp16 UT

* 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][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

* [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)`