[Clean fluid] Clean ones, reverse, save, save_combine, load_combine, has_inf, zeros_like and ones_like (#48424)

* Clean fluid ones

* clean ones_like

* clean zeros_like

* clean save,save_combine,load_combine

* clean reverse

* clean has_inf

* clean reverse tests

* add nparray case for basic operator

* fix unit test

* fix unit test

* add unit test

* fix unit test

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* [CodeStyle] remove all future import

* revert test_error.py

* restore future import in example code

[CodeStyle] use np.testing.assert_allclose instead of self.assertTrue(np.allclose(...)) (part 2) (#45213)

* autofix (get ci log)

* retrigger ci

* fix test_gather_nd_op, wrong expected in dygraph

* fix test_activation_op, unpack static graph result

* fix test_auc_op, unpack static graph result

* fix test_bce_loss, unpack static graph result

* fix test_bce_with_logits_loss, unpack static graph result

* fix test_cond, unpack static graph result

* fix test_dygraph_weight_norm, wrong numpy reference when `axis=None`

* fix test_einsum, wrong matmul inputs

* fix test_elementwise_heaviside_op, unpack static graph result

* fix test_frac_api, unpack static graph result

* skip test_group_norm_op_v2, probably the wrong numpy reference

* fix test_imperative_double_grad, wrong subscript

* skip test_imperative_tensor_clear_gradient, ???

* skip test_layer_norm_op, probably the wrong numpy reference

* fix test_math_op_patch, unpack static graph results

* fix test_masked_select_op, unpack static graph results

* fix test_mse_loss, unpack static graph results

* fix test_multi_label_soft_margin_loss, unpack static graph results

* fix test_multi_dot_op, unpack static graph results

* fix test_nll_loss, unpack static graph results

* fix test_normalization_wrapper, unpack static graph results

* fix test_pass_builder, unpack static graph results

* fix test_prelu_op, possibly an extra comma

* fix test_psroi_pool_op, unpack static graph results

* fix test_queue, unpack static graph results

* fix test_reorder_lod_tensor, compare an item with a list

* fix test_rrelu_op, unpack static graph results

* fix test_searchsorted_op, unpack static graph results

* fix test_sigmoid_focal_loss, unpack static graph results

* fix test_smooth_l1_loss, unpack static graph results

* fix test_soft_margin_loss, unpack static graph results

* fix test_softmax2d, unpack static graph results

* fix test_square_error_cost, unpack static graph results

* fix test_tril_indices_op, unpack static graph results

* fix test_unsqueeze_op, mismatch numpy reference (axis)

* skip test_layers, `static_rlt` is missing an axis

* fix test_mnist, unpack PredictorTools result (also a list)

* fix test_build_strategy, unpack PredictorTools result

* fix test_mobile_net, unpack PredictorTools result

* fix test_resnet_v2, unpack PredictorTools result

* revert some changes

revert test_layers

revert test_group_norm_op_v2

revert test_layer_norm_op

revert test_imperative_tensor_clear_gradient

* fix test_normal, use flatten instead of reshape, (PR-CI-Windows-OPENBLAS)

* empty commit, trigger CI

[CodeStyle] use np.testing.assert_array_equal instead of self.assertTrue(np.array_equal(...)) (#44947)

* automatically fix

* update comments

* numpy -> np

* self.assertEqual(..., True)

* wrong usage (err_msg=True)

这不是修复导致的错误，这些是原来 `self.assertTrue(..., True)`
的错误用法，因此在修复后将其认为位置参数 `err_msg`

* some missing fix

* 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

* pass stop_gradient for cast op

* improve performance of elementwise_add grad

* use tensor copy async

* dygraph branch

* fix dygraph branch

* add ut

* check and fix tensor and scalar type promotion

* fix else branch error

* fix scalar method error

* fix test_math_op_path unittest

* add future division for unittest

* rm useless bin file

* add div, floor_div, remainder

* add unittests, test=develop

* set dtype of compare op to bool, test=develop

adds unary operator __neg__ for VarBase in dygraph mode, and for Variable in static graph mode.

Support backward of backward for Relu and add a new gradient checker by comparing theoretical and numerical Jacobian. (#16862)

* Support backward of backward and a new gradient checker
* Rename decorators.py to decorator_helper.py, since Python on Windows CI has decorators package.

1. Add ReluDoubleGradMaker when register relu_grad.
2. Add a new gradient checker by comparing theoretical and numerical Jacobian.  Check double gradients by double_grad_check.

When the second argument contains batch dimension, the axis should be 0.

Also makes elementwise ops more tolerant at handling tensors with trailing
singular dimensions.

Currently, our tests run with 2 GPUs, the init time is absurdly long:
about 4s for each process.  Currently, we run each OP test on
different processes. This PR:

1. create cmake function py_test_modules which will generate the
Makefile that runs a list of Python unittest module in a single Python
process.

2. move all "python unittest compatible" (e.g., used the unittest
package, not just a regular python file). from fluid/tests to
fluid/tests/unittests.

3. cmake now will run all OP tests in fluid/tests/unittests in a
single process, except the time-consuming tests, they are separated
into different processes to utilize parallelism. Please make sure to
use the unittest package if you put the python test file in
fluid/tests/unittests

4. remove all exit(0) from fluid/tests/unittests/*.py, exit(0) is used
to disable unittest, we can not do it when running all tests in a
single process since it will terminate the process without running the
other tests. Instead, the test is disabled in
fluid/tests/unittests/CMakeLists.txt. FIXME is added for each disabled
item. Please disable the unittest from
fluid/tests/unittests/CMakeLists.txt, instead of adding exit(0) to the
Python file, for all Python file in fluid/tests/unittests/.

5. add an option WITH_FAST_BUNDLE_TEST. When OFF, will run the unit
tests in separate process so that they can be tested individually.

Users can use `a+b`, `a*10`.