[optimizing] Name the last DCE pass.

This will allow Checker to differentiate between them.

Change-Id: I972d452a64f1c19d370567b9ef3d620f9b835a9a
diff --git a/compiler/optimizing/dead_code_elimination.h b/compiler/optimizing/dead_code_elimination.h
index 3f309c5..cee9364 100644
--- a/compiler/optimizing/dead_code_elimination.h
+++ b/compiler/optimizing/dead_code_elimination.h
@@ -29,8 +29,10 @@
  */
 class HDeadCodeElimination : public HOptimization {
  public:
-  HDeadCodeElimination(HGraph* graph, OptimizingCompilerStats* stats)
-      : HOptimization(graph, true, kDeadCodeEliminationPassName, stats) {}
+  HDeadCodeElimination(HGraph* graph,
+                       OptimizingCompilerStats* stats = nullptr,
+                       const char* name = kDeadCodeEliminationPassName)
+      : HOptimization(graph, true, name, stats) {}
 
   void Run() OVERRIDE;