Fuse softmax(a + b) in case of simple broadcast (#4937)
* bias softmax kernel
* bias softmax kernel
* remove debug comments
* remove debug comment
* windows build doesnt handle unary minus on unsigned type
* int64 => int treated as error
* only support cuda
* add bias softmax fusion tests
* PR comments
* more PR comments
* use MLTypeCallDispatcher
* break function into pieces
* add loop unroll and add to list for inference as well
* use std::min and move operator==
* revert std::min (doesnt work ci pipeline) and fix int to size_t error
* pr comments
* fixes for windows ci
* fix for windows ci
* pr comments on consistency
* p_model_
* fix formatting and add anonymous namespace
Co-authored-by: suffian khan <sukha@OrtTrainingDev1.af05slrtruoetgaxwwjv5nsq5e.px.internal.cloudapp.net>
