fixup! [MCA] Do not allocate space for DependenceEdge by default in DependencyGraphNode (NFC)

Author: asi-sc

llvm/tools/llvm-mca/Views/BottleneckAnalysis.h

@@ -228,6 +228,9 @@ class DependencyGraph {
     unsigned Depth;
 
     DependencyEdge CriticalPredecessor;
+    // Measurements show that more than 90% of nodes have no outgoing edges. To
+    // minimize memory consumption we use SmallVector with zero inline elements
+    // that is preferred version of std::vector.
     SmallVector<DependencyEdge, 0> OutgoingEdges;
   };
   SmallVector<DGNode, 16> Nodes;