IR: Fix the mnist and cifar tests by passing the result of the softmax node, and not the node itself. This failure was cought by the IR verifier.

Author: nadavrot

examples/cifar10.cpp

@@ -96,7 +96,7 @@ void testCIFAR10() {
     auto *FCL1 = bb.createFullyConnectedOp(*MP2, 10);
     auto *RL3 = bb.createRELUOp(*FCL1);
     auto *SM = bb.createSoftMaxOp(*RL3, E);
-    result = bb.createReturnOp(SM);
+    result = bb.createReturnOp(*SM);
   }
 
   IP.optimize();

examples/mnist.cpp

@@ -89,7 +89,7 @@ void testMNIST() {
     auto *RL2 = bb.createRELUOp(*FCL1);
     selected = bb.createWeightVar(ElemKind::IndexTy, {minibatchSize, 1});
     auto *SM = bb.createSoftMaxOp(*RL2, selected);
-    result = bb.createReturnOp(SM);
+    result = bb.createReturnOp(*SM);
   }
 
   IP.optimize();