- Support setting attr in config
- Support setting dtype and initializer for input in config
test=develop

Optimize the CUDA implementation of sequence_expand op by reduce the times of copying lod data from CPU to GPU. (#15493)

* Optimize the CUDA implementation of sequence_expand op by reduce the times of copying lod data from CPU to GPU.
test=develop

* Refine the op benchmark to support setting lod in config.
test=develop

* Initialize the benchmark tester for operator.
test=develop

* Rearrange the codes.
test=develop