* move fft kernels to phi, done with cufft, pocketfft, mkl_cdft, hipfft
* make stft_op use fft from phi/kernels/funcs, clean code

* Move api(lgamma) from legacy_api.yaml to api.yaml

* Move api(lgamma) from legacy_api.yaml to api.yaml

* Move api(lgamma) from legacy_api.yaml to api.yaml

* modify code style

* add x to X mapping

* add definition of lgamma

* delete redundant lgamma definitions

* Modify code comments

* Modify ops.py code format

* add lgamma  single test and lgamma api in fluid

* Optimized lgamma unittest

* migrate solve kernel to phi

* re useless header file, fix a bug in grad_kernel_impl

* add header file in need

* add yaml for solve op

* fix solve_sig.cc ArgumentMapping and update tests case

* disable legacy dygraph check in op_test

* rm solve_op.cc / solve_sig.cc and migrate yaml config

* Update op_test.py

disable legacy dygraph check when check_eager is True

* remove auto to_pascal_case for args in op generator

* fix yaml config

* move yaml to phi

* fix undef var error

* move cross form legacy_api.yaml to api.yaml

* move diagonal to api.yaml

* move apis from legacy_api.yaml to api.yaml

* remove comment

* revert argsort

* fix merge conflict

* move trace into api.yaml

* add trace unittest

* fix trace test

* fix generate op