Improved c1visualizer output a bit: Emit a human-readable description for

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
===================================================================
--- src/hydrogen-instructions.h	(revision 7845)
+++ src/hydrogen-instructions.h	(working copy)
@@ -628,7 +628,9 @@
   // Printing support.
   virtual void PrintTo(StringStream* stream) = 0;
   void PrintNameTo(StringStream* stream);
-  static void PrintTypeTo(HType type, StringStream* stream);
+  void PrintTypeTo(StringStream* stream);
+  void PrintRangeTo(StringStream* stream);
+  void PrintChangesTo(StringStream* stream);
 
   const char* Mnemonic() const;
 
@@ -741,6 +743,8 @@
     SetBlock(block);
   }
 
+  void PrintMnemonicTo(StringStream* stream);
+
   HInstruction* next_;
   HInstruction* previous_;
   int position_;