* add pybind interface to get all inplace ops, test=develop

* enhance OpTest to check whether the consistency of operator when using and not using inplace, test=develop

* handle corner cases in op_test, test=develop

* support outputs without tensor holder_, like XShape in reshape_op, test=develop

* fix bug, some op has GradOpMaker, but actually no grad_op in OpInfoMap, test=develop

* use reshape_grad instead of reshape in FlattenGradOp, test=develop

* fix error debug dims info for variables like XShape, test=develop

* change computational order in sum_op to relieve computation difference using inplace, test=develop

* add inplace_atol to check group_norm, and skip inplace_grad for mkldnn, test=develop

* follow sneaxiy's comments, test=develop

* remove unused DefaultGradOpDescMaker in mkldnn op, test=develop

* Enhance the error message when GrapOpMaker is null.
test=develop

* Call Proto() instead of directly using proto_ pointer.
test=develop

* Rollback to use proto_ directly, because some sepecial grad ops, such some double grad ops, donot have proto.
test=develop

test=develop

refine gc code
test=develop

test=develop

This reverts commit 1d91a49d.

* some trivial opt

* remove the fix of lod_tensor and shrink_rnn_memory_op

* refine ShrinkRNNMemoryOp

test=develop

* Move framework.proto to proto namespace

* Fix compile

* Fix compile

* Fix Compile

* Op developer can add `InferShape` to any operator

* Add print_operators_doc.cc

* Update Escape

* Correct a bug

* Remove OpInfoMap::Iterate

* Update the print_operators_doc.cc

* Escape tab

* Use auto&

* Use auto&

* Remove trailing ,

* clang-format C++

* Add Get/Has methods to OpInfoMap
* Add PADDLE_ENFORCE for OpInfo to get field.

Fix cycle dependencies, Fix #3583.

* Also simplify pybind implementation by using OperatorBase as holder
  type.

* add NDEBUG switch to PADDLE_ENFORCE