* addd

* add cast_op_xpu, test=kunlun

* fix bug for cast_op_xpu,test=kunlun

* add concat_op_xpu, test=kunlun

* slove conflicts, test=kunlun

* fix bug,test=kunlun

* add assign_op_xpu, test=kunlun

* fix bug,test=kunlun

* test=kunlun;test=develop

* fix concat bug,test=kunlun

* fix check_dygraph set in test_concat_op_xpu.py,test=kunlun

* fix error message,test=kunlun
Co-authored-by: Nmapingshuo <mps2012@yeah.net>