faster the compare ops dygraph model speed 

* add lars to fleet meta optimizer

* add lamb to proto

* add lamb to fleet meta optimizer

* fixed syntax bug

* fixed syntax bug

* fixed syntax error in lamb, add config setter of lamb in distributed_strategy

* trigger unitest to rerun

* add new unitest func for lamb

* revise unitest for lars and lamb

* revise dgc meta unitest

* revise lars document in distribute_strategy

* revise lars lamb document in distributed_strategy.py

* revise lars lamb document in distributed_strategy.py

* add weight decay exclude logic to lars

* restore optimzier.py

* restore optimizer.py as develop except lars

* add epsilon and exclude fn to distributed_sttrategy

* add lars epsilon

* revise unitest for fleet lars and lamb

* revise lars lamb unitest for CI coverage

* revise lars argument api

* revise lars argument api

* revise lars argument api

* revise api doc of lars

* fix op role

* add sharding save and add_sync_comm_for_test function

* add comm_analyse to utlis

* revise sharding_utils

* add sharding saving unittest

* revise sharding utils for unittest

* update interpolate, test=develop

* fix coverage, test=develop

add two paddle-2.0 apis: paddle.static.io.save_inference_model and paddle.static.io.load_inference_model (#28606)

* add two apis: paddle.static.io.save_inference_model and paddle.static.io.load_inference_mode, which are campatible with paddle.fluid.io.save_inference_model and paddle.fluid.io.load_inference_model respectively.

* add unittest for new save_inference_model and load_inference_model. test=develop

* enhance doc. test=develop

* add paddle.enable_static() to test_inference_model_io.py. test=develop

* add debuging code

* change seed & add debug message

* support user-defined quant and preprocess

* add matmtl_v2 to amp list

* support dygraph

Fix a bug that used in PaddleGAN model which used `isinstance` in a for loop

* adapt pad const

* fix comment and rm fluid import

* rm stdout

* fix note

* fix output dtyp inconsistent with input

* refine code

fix the gradient bug for the topk v2 

* add WeightedRandomSampler. test=develop

* Add checkpoint to quantize

* Change bfloat16 option

* add mkldnn inplace op version test

* update mkldnn_inplace fuse pass

* update the inplace test

* fix test_multinomial

* fix test_multinomial add 0 prob

* DataLoader support not auto collate batch. test=develop

PaddleSeg uses tuple as parameter of transpose in dygraph code:
https://github.com/PaddlePaddle/PaddleSeg/blob/release/v0.7.0/dygraph/paddleseg/models/danet.py#L152

However, in dy2stat, static code doesn't support the perm as a tuple. This PR fixed it.

* Fix gradients with ignore_idx in softmax_with_cross_entropy.
test=develop

* Fix gradients with ignore_idx in softmax_with_cross_entropy on cpu.
Remove softmax_with_cross_entropy from op_threshold_white_list.
test=develop

* Fix test_softmax_cross_entropy_op.py.
test=develop

I found the unittest failed due to batch size. Maybe the reason is that our CI machine has limited memory. I decreased the batch size.

* update, test=develop

this is a preemptive measure, the unit test was failing occasionally with
cudnn internal error

* add onnx export module, test=develop

* add unit test for paddle.onnx.export

* adjust api & doc

* fix some typo

also fix `no_grad` alias

* skip_layernorm_op done

* add unittest

* slice op convertor support trt < 6

* skip_layernorm only work in ernie

As the title

1. Remove 'fluid';
2. Variable -> Tensor

APIs:
 sum, convert_call, convert_ifelse,
 convert_logical_and, convert_logical_or, convert_logical_not

Modify ProgramTranslator and TracedLayer Doc for API 2.0

Remove "fluid", "variable" in 2.0 API doc

As the title