Remove unused method HType::IsTagged().

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 2ab6c890a4043b920583faf1ac21ffff6b322ef7..aa2cdae0a83190b00c7dbdd132f9066e518f49ae 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -374,10 +374,6 @@ class HType V8_FINAL {
     return Combine(other).Equals(other);
   }
 
-  bool IsTagged() const {
-    return ((type_ & kTagged) == kTagged);
-  }
-
   bool IsTaggedPrimitive() const {
     return ((type_ & kTaggedPrimitive) == kTaggedPrimitive);
   }