GradMaker for dygraph (#19706)
* refactor dygraph,test=develop
* fix failed unittest,test=develop
* polish code,test=develop
* check windows ci error,test=develop
try to fix windows ci error by np.allclose,test=develop
* polish vlog and profiler, test=develop
* try to fix preceding ops order,test=develop
* test transformer in windows ci, test=develop
* use python c-api to speed up tracer.trace,test=develop
* test=develop, fix docker with paddle nccl problem
* test=develop, add ut for debug string and gradient_accumulator
* test=develop, add tests for layer/gradient_accumulator/prepared_op
* test=develop, fix complie error for test_prepared_op
* test=develop, add more ut for dygraph
* test=develop, create API.spec for dygraph api change
* optimize grad maker; test=develop
* optimize grad maker
* test
* grad make optim; test=develop
* fix unittest bugs; test=develop
* add dygraph grad op maker and split_op
* grad op maker refactor; test=develop
* add dygraph grad maker; test=develop
* fix op deformable_conv_v1_op bug; test=develop
* fix deformable_conv prroi pool bugs;
* fix new op grad op maker bug; test=develop
* fix split by ref bug; test=develop
* fix dygraph auto prune bug; test=develop
* fix test_trace bug; test=develop
* fix fused emb seq pool bug; test=develop
* remove useless code in op_desc file; test=develop
* remove useless code, StrVarBaseNode; test=develop
* fix review issues; test=develop
* fix rank_loss grad maker; test=develop
* remove flag in VarBase; test=develop
* fix distributed_notify_op compile bug ; test=develop
* fix reshape op double grad; test=develop
* fix expand as op; test=develop
* add impertive type_defs.h for demo_train; test=develop
* fix inference lib cmake; test=develop
* fix inference lib; test=develop
* fix infernce_lib; test=develop
* fix inference cmake; test=develop
* fix inference lib; test=develop
* fix inference lib; test=develop
* remove condition dygraph grad maker, modify local name; test=develop
* fix split grad maker bug; test=develop
* fix pyramid_op bug; test=develop
* change travis time out limit; test=develop
* restore travis; test=develop
* change timeout limit; test=develop
hong
8c4573a3cb