gen_bw_fn return maybe (#5454)

* modified SetInputArgModifyFn

* Delete the CHECK changes in the assign_op.cpp file

* Format

* Modified the OutputArgModifyFn interface

* add return

* maybe error stack from CheckAndConstructOp to OutputArgModifier callback function

* maybe error stack from CheckAndConstructOp to OutputArgModifier callback function

* OutputArgModifier return maybe part_1

* maybe error stack from CheckAndConstructOp to OutputArgModifier callback function

* input_arg_modifier return maybe

* gen_bw_fn return maybe

* add MakeGenBackwardOpConf because ofstatement-expression not allowed outside function resulting in JUST failed in lambda

* add maybe after merge master

* fix bug: JUST in lambda

Co-authored-by: aishangjj <702572275@qq.com>
Co-authored-by: oneflow-ci-bot <69100618+oneflow-ci-bot@users.noreply.github.com>