A few small refactorings and typo fixes

src/hydrogen-mark-unreachable.h

Index: src/hydrogen-mark-unreachable.h
diff --git a/src/hydrogen-mark-unreachable.h b/src/hydrogen-mark-unreachable.h
index e9459d5208c2963c1784330fccc43222ab620bed..9ecc6e9f164a0e66b2aa3e9a652e49b9a77c6389 100644
--- a/src/hydrogen-mark-unreachable.h
+++ b/src/hydrogen-mark-unreachable.h
@@ -37,7 +37,7 @@ namespace internal {
 class HMarkUnreachableBlocksPhase : public HPhase {
  public:
   explicit HMarkUnreachableBlocksPhase(HGraph* graph)
-      : HPhase("H_Mark unrechable blocks", graph) { }
+      : HPhase("H_Mark unreachable blocks", graph) { }
 
   void Run();