* Support to use external function test=develop

* refine the parms of ast_to_func test=develop

* support to modify dict and list in while_loop test=develop

* polish code test=develop

* fix div zero test=develop

* fix div zero test=develop

* add hostdevice function test=develop

* add eps when is zero test=develop

1. Add support for Break and Continue in Dygraph to Static
2. Also add support for gast.Not in NodeTestTransformer
3. Also add support for logical op transformation in LoopTransformer

* don't add unregisterd attr, test=develop

* add some unittests,test=develop

This reverts commit 66fce9e8.

* Support and/or in controlFlow if test=develop

add approximation for gelu, default value is False (only kernel with eigen is added, remove code for computing gelu with MKLDNN temporarily)

test=develop

Fleet Parameter Server API Integrated

* Improved stability through the use of caching

test=develop

* fix style

test=develop

* Fix syntax error

test=develop

* Fix syntax error

test=develop

* Support Tensor.shape in control flow if/for/while and separate TensorShapeTransformer from BasicApiTransformer. test=develop

* remove the fill_constant_batch_size_like,  gaussian_random_batch_size_like and uniform_random_batch_size_like_cn three Op unittest 

* add transpose_flatten_concat_fuse_pass tests for gpu and trt, test=develop

* update test_inference_api.py, test=develop

* Support and/or in controlFlow if test=develop

* Refine IsControlFlow interface test=develop

* fix the travic ci problem

* add fusion group test for backward and refine code

* Support that the input(x) of stack api is a LoDTensorArray. test=develop

* Support that the input of concat api is a LoDTensorArray. test=develop

* Add tests to test stack/concat called in dygraph_to_static. test=develop

* support list in control flow if. test=develop

* support list in for/while and supplement tests. test=develop

* add support for expression type convert and add cast Op support in fusion group

* update

* update test=develop

* update compile set test=develop

* update compile set test=develop

* update test=develop

* update test=develop

* update test=develop

* update compile setting test=develop

* update compile setting test=develop

* update run demo test=develop

* update test=develop

* update test=develop

* fix test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update format test=develop

* update format test=develop

* update style test=develop

* update style test=develop

* change style test=develop

* change style test=develop

* change style test=develop

* add dataset unittest test=develop

* update test=develop

* update for record test=develop

* udpate style for record test=develop

* update for record test=develop

* update for record test=develop

* update for record test=develop

* fix format test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* update test=develop

* fix compile warning test=develop

* add attr default test=develop

* add unittest test=develop

* fix style test=develop

* fix style test=develop

* change out_val_ifempty to out_val_if_empty test=develop

1. Add basic support for `for in range` loop
2. Move `test_dygraph_to_static_*` to `dygraph_to_static` dir and rename them
3. Add test case for dict in while_loop

* add skip_layernorm pass. test=develop

As the title

* 1. add embedding eltwise layernorm fuse
2. add embedding eltwise layernorm op
3. refine inplace_add_relu
4. refine fc_eltwise_layernorm
test=develop

* 1. refine fc
test=develop

* fix comments
test=develop

* fix comments

test=develop

+ Refine code structure and move code related with control flow `if` into `ifelse_transformer.py`
+ Merge code of `ast_utils.py`  into `utils.py` 

As the title.

* refine grad maker, test=develop

* refactor tracer stage 1, test=develop

* merge develop to solve conflict third times, test=develop

* fix API param bug of recompute.backward(), test=develop