* add cycle_gan_model

* align train test=develop

* modify image_size into 64 to avoid TimeOut test=develop

* TODO in GPU test=develop

* test=develop fix conv3d_transpose_test error

test=develop

fix sample code error of fluid.dygraph.NaturalExpDecay

* Refine caches of converting func test=develop

* fix if statement test=develop

* refine cache code test=develop

* rm unuse import statement test=develop

* Polish code comment test=develop

* Refine check_type for @declarative test=develop

* add new api (set_global_initializer/reset_global_initializer),test=develop

* add new api (set_global_initializer/reset_global_initializer),test=develop

* fix doc and example code of set_global_initializer,test=develop

* add for iter var list, test=develop

* add enumerate unittest, test=develop

* Start implementing int8 eltwise add

test=develop

* - Fix to Michal PR

* - Fix

test=develop

* - Lint fixes

test=develop

* - Added checking if elementwise_mul can be used

test=develop

* - Added attribs to skip_attrs_set

test=develop

* - Improved broadcasting

test=develop

- fixes to compilation

- fix

- fix

- Lint fixes

test=develop

* - removed redundant condition

test=develop
Co-authored-by: NMichal Gallus <michal.gallus@intel.com>

* add relu for lenet, test=develop

* fix test model, test=develop

* The arg of append() can be not Tensor temporarily.

* Add Seq2Seq as ProgramTranslator Unit Test. 

* set dtype of vocab_size_tensor to int64 to pass Windows-CI. 

* fix bug of prelu when rank not equal 4, test=develop

* fix prelu inference, test=develop

* fix api, test=develop

* fix shape when mode is chennel, test=develop

* remove debug code, test=develop

* add unittest, test=develop

As the title

* Add a StatValue class in the backend to represent a stat.
* Add a singleton StatRegistry to maintain the collection of stats.
* For the sake of code neatness, we only support type of int and float, which can cover most of the scenarios.

Some big models can timeout on Windows CPU machine. I added some timeout properties.

Add TSM as ProgramTranslator Unit Test. The TSM code is referred from PaddlePaddle/models#4229

* add MobileNet unittest test=develop

* fix cudnn random test=develop

* fix sync barrier with barrier monitor, test=develop

* enable load_program_state run in imperative mode; test=develop

* remove useless code; test=develop

[Dy2Static]Convert var.shape stmt and Convert the return variables of Tensor-dependent 'if' staments to Tensor if it not  (#24911)

* Support int and long: int or long -> six.integer_types. 

* Modify test_tensor_shape: fix bug and modify comment. 

* Support convert_var_shape to convert var.shape stmt

* Modify code in ifelse_simple_func.py because don't support return non-Tensor in Tensor-dependent 'if' stament currently. 

* Convert the return variables of Tensor-dependent 'if' staments to Tensor if it not. test=develop

[Dy2stat] decrease the batch size to decrease GPU usage.

* Move function 'convert_len' to file convert_operators.py 

* Support that for statements are transformed to while statements.

* Fix bug: raise None -> return None. 

* Support variable loaded and created in loop.

* Use int64 in Py2 and Py3 in function to_static_variable.

Fix the bug for elementwise_div op, when the first var is scalar; Use the shape 1 replace the -1 in shape.

[Dy2stat] Add word2vec as unittest

Add the support the 5d,6d tensor support for the reduce ops;
Add the same time, the compile time, it was 22 minutes, it was 21 minutes after fixed.

test=develop