* add_n and combine support selected rows

* done replaced in d2s models, except lac/transformer/sentiment

* replace cinn_test

* fix d2s transfomer model

* fix cinn model ut

* move DataLoader to paddle.io. test=develop

* add enable_to_static and drop some methods of ProgramTranslator

* fix code style

* fix cant import enable_to_static and update unitest

* change unitest and rollback code of PT

* fix can't import as of utils

* roll back PT

* fix roll back

* add some unitest

* add unitest and fix codestyle bug in api.py

* finish all unitest

* remove ProgramTranslator

* fix code style

* restore test_program_translator

* api.py remove get_func

* TestDygraphToStaticCode

* fix check_type and import err

* roll back PT without getcode

* roll back pt with get_code

* convert_to_static

* fix import __all__

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

* fix an increment

* 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

* [Eager] Remove enable_legacy_dygraph setting

* Add more tests

* test=py3-eager

* test=py3-eager

* test=py3-eager

* rename manual_seed to seed

* rename xxx1d-->xxx1D, xxx2d-->xxx2D, xxx3d-->xxx3D

* rename manual_seed --> seed

* do not rename .cc, .cu and .h file

* rename manual_seed --> seed

* rename manual_seed --> seed

* rename manual_seed --> seed

* rename manual_seed --> seed

* disable_static on doc example code

* donot change manual_seed on generator

* add enable_static on sample code

* convert python/paddle/fluid/layers/nn.py to bak

* fix typo

* fix code style

* fix seed to manual_seed when call functions of Generator()

* fix bug

Add Simnet Test for V2 APIs.

We used tool from https://www.paddlepaddle.org.cn/documentation/docs/zh/2.0-beta/guides/migration_cn.html#paddle1-xpaddle2-0beta to do v1.x to v2 transformation.

This PR pulled changes from #27430, please DO NOT merge before #27430 is merged

* refine manual seed

* fix ci problem

* fix unittests

* fix unittest

* set is_init_py=false in manual_seed

* fix unittest

* fix bernoulli_op

* fix(unittest): change random_seed to manual_seed

* 🐞fix(unittest): fix manual_seed

* trigger ci

* fix test_sentiment

* fix test_imperative_save_load

* fix test_uniform_random_op

* fix test_uniform_random_op

* fix test_jit_save_load

* merge develop

* fix manual_seed

* fix manual_seed

* use global engine

* use shared_ptr

* fix double free

* fix bug

* fix bug

* fix bug

* fix test bug

* fix test bug

* fix test bug

* fix ci

We found that the reason of multiple return error in SimNet is that I wrote wrong task_mode. If we set task_mode as "pairwise" correctly, which is a format of the model input data, the multiple return won't have problem in the unit test. In this PR we corrected the task_mode and enable multiple return in SimNet unit test.

Add Support for SelectedRows for Transpose OP and Fix a Bug That SelectedRows Cannot be Supported in SimNet (#25536)

This PR fixes a bug that SelectedRows cannot be supported in SimNet. The reason of this bug is that dygraph basic_engine didn't copy var's type when the var needs to be accumulated during backward. So when a var is SelectedRows and needs to be accumulated, like SimNet which calls net for two times, the var's type will be changed to default LoDTensor thus bug happens. To fix it, we just also copy the type.

Without this PR, the accumulated SelectedRows parameters in dygraph will be changed into LoDTensor. So when we fixed the bug of supporting SelectedRows in SimNet, we found `test_imperative_lod_tensor_to_selected_rows` failed and threw the error that SelectedRows was not supported for Transpose OP. To fix it, too, this PR also added support for SelectedRows for Transpose OP.

Add Similarity Net as unit test. During the unit test, we found three problems:

1. The run_program_op has memory optimization error when running dy2stat net multiple times.
2. The support for SelectedRows can cause problem in dy2stat.
3. The return grammar has problem.

This PR fixes the 1. problem but modify codes for the 2. 3. problems to make PR smaller. I will fix those two problems in the next PR(s)