Fix a small bug in trace printing for discovered loops.

runtime/vm/flow_graph.h

Index: runtime/vm/flow_graph.h
diff --git a/runtime/vm/flow_graph.h b/runtime/vm/flow_graph.h
index 8ed08c8d125b59778f48be1db4421757afd4c781..615cef1c1575d0426703eab2a6e49956fb00f4e0 100644
--- a/runtime/vm/flow_graph.h
+++ b/runtime/vm/flow_graph.h
@@ -218,6 +218,11 @@ class FlowGraph : public ZoneAllocated {
   void ReplacePredecessor(BlockEntryInstr* old_block,
                           BlockEntryInstr* new_block);
 
+  // Find the natural loop for the back edge m->n and attach loop
+  // information to block n (loop header). The algorithm is described in
+  // "Advanced Compiler Design & Implementation" (Muchnick) p192.
+  void FindLoop(BlockEntryInstr* m, BlockEntryInstr* n);
+
   // Finds natural loops in the flow graph and attaches a list of loop
   // body blocks for each loop header.
   ZoneGrowableArray<BlockEntryInstr*>* ComputeLoops();