* support layer_norm prim and cinn test

* enable cinn test

* fix merge conflict

* polish input for check_output_with_place

* fix merge conflict

* add more test case

* fix merge conflict

* polish test case

* polish op_test

* change ln_g rules

* modify scale is none case

* modify scale is none case

* add public_python_api for check prim

* modify setoutputgrad and fp64bug

* add todo & delete log

* delete Single***varname

* delete get varname

* modify FP64 bug

* delete op test

* recover

* fix conflict

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Co-authored-by: NWeilong Wu <veyron_wu@163.com>