* add_dygraph_execution_context

* add dygraph infershape context and execution context; test=develop

* fix imperative bug; test=develop

* remove inputs outputs interface from execution context,
because it have same function with inputNames;
test=develop

* remove tracer_test ctest; test=develop

* fix split op bug; test=develop

* fix unitests bug; test=develop

* fix distribute test bug; test=develop

* fix ngraph compile bug; test=develop

* fix grad maker bug; test=develop

* fix load op bugs; test=develop

* fix operator.cc construct bug; test=develop

* remove useless name find in operator; test=develop

* add tracer_test; test=develop

* fix concat, split bug; test=develop

* remove tracer_test unitest; test=develop

* fix attribute check bug; test=develop

* add test code to fix converage; test=develop

* remove useless code, change check backward input in engin; test=develop

* unlock var type infer shape;test=develop

* add ShareAllLoD api; test=develop

* add dygraph infershape context unitest; test=develop

* remove increase and decrease lod in dygraph; test=develop

* addd override; test=develop

* fix increase descrease lod; test=develop

* fix paddle_enforce; test=develop

* disable lod op dygraph check; test=develop

* fix paddle enforce error; test=develop

* add comment for op_registry and OperatorBase; test=develop

* optimize the comment of op_registry; test=develop

* fix format of comment; test=develop

* fix format of comment; test=develop

* optimize the format of comment; test=develop

* optimize the format of the comment; test=develop

* optimize comment of op_registry; test=develop

* remove -Wno-error=sign-compare, make warning as error

test=develop test=document_fix

* fix exist compile warning

test=develop

* add axis check for concat op
test=develop

* fix PADDLE_ENFORCE format
test=develop

* move to ComputeAxis for InferShape check
test=develop

support Tensor for split and concat, support -1 in num_or_sections, add check num_or_sections (#20780)

* improve split and concat op:
1. support Tensor for argument 'dim' in split op.
2. support Tensor for argument 'axis' in concat op.
test=develop

* redefine function GetDataFromTensor and set unknown output shape to - 1.
test=develop

* add check: Attr(sections) match Input(X). test=develop

* support Tensor for attr(sections) and attr(sections) can contain -1.
add check for attr(sections).
test=develop

* modify error message for concat and call Resize only when necessary. test=develop

test=develop

* enhance_concat, test=develop

* speedup split_op
test=develop

* speedup split_op
test=develop

* rename ConcatGrad to Split

* refine concat and split
test=develop

* fix compile error

* Fix CPPLint issues in lstm_cpu_kernel.h

* Fix CPPLint issues in math/math_function_test

* Fix CPPLint issues in math/math_function_test

* Fix CPPLint issues in math/concat.cc

* Fix CPPLint issues in math/concat.cc

* Fix CPPLint issues in math/concat.cc

* Fix CPPLint issues in math/gru_cpu_kernel

* Fix CPPLint issues in math/selected_rows_functor_test.cu

* Fix compile error

* Fix compile error

* "try enhance concat op"

* "enhance the concat operator"

There are mainly following fixes:

- take `DeviceContext` as the template parameter of math functors and OpKernel instead of `Place`
- remove `eigen_device` interface in base class  `DeviceContext`
- remove `GetEigenDevice` interface in `ExecutionContext` and base class `DeviceContext`
- remove unused `platform::EigenDeviceConverter`
- rename `REGISTER_OP_GPU_KERNEL` to `REGISTER_OP_CUDA_KERNEL`
- rename `USE_GPU_ONLY_OP` to `USE_CUDA_ONLY_OP`

User StridedMemCpy in Concat/Split Op

add concat op with CPU kernel