Only fuse when output count of add is 1

Author: yufenglee

onnxruntime/core/optimizer/skip_layer_norm_fusion.cc

@@ -25,7 +25,8 @@ static bool IsSupportedDataType(const Node& node) {
 
 static bool CheckFirstAdd(Node& add, ProviderType providertype) {
   if (providertype != add.GetExecutionProviderType() ||
-      !IsSupportedDataType(add)) {
+      !IsSupportedDataType(add) ||
+      add.GetOutputEdgesCount() != 1) {
     return false;
   }
 
@@ -58,7 +59,8 @@ static bool CheckFirstAdd(Node& add, ProviderType providertype) {
 // The 2nd input should be a 1D constant value
 static bool CheckSecondAdd(Node& add, ProviderType providertype) {
   if (providertype != add.GetExecutionProviderType() ||
-      !IsSupportedDataType(add)) {
+      !IsSupportedDataType(add) ||
+      add.GetOutputEdgesCount() != 1) {
     return false;
   }