Mindspot rewrites withlosscell, traionestepcell interface

Error: runtimeerror:_kernel.cc:88 CheckParam] AddN output shape must be equal to input shape.Trace: In file add_impl.py(272)/ return F.addn((x, y))/

Solution: do not return multiple parameters in the construct method of withlosscell, otherwise an error will be reported in the gradoperation in the construct of traionestepcell.