onnxruntime

9f5d4918 - MatMul Gradient optimization for dB when B's is 2D tensor (#4899)

MatMul Gradient optimization for dB when B's is 2D tensor (#4899) * Optimized MatMulGrad for dB when B's shape is 2D * Refactor for ConstantScalarNode Co-authored-by: Sherlock Huang <bahuang@OrtTrainingDev3.af05slrtruoetgaxwwjv5nsq5e.px.internal.cloudapp.net>