Improve elements validation and object printing

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 90e11e3d6cccbc10323287f2250452ea74889cf0..737b9f3f29ae845155a4c1d989e57c78d0d1978e 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -41,12 +41,12 @@ class BuiltinArguments : public Arguments {
   }
 
   Object*& operator[] (int index) {
-    DCHECK(index < length());
+    DCHECK_LT(index, length());
     return Arguments::operator[](index);
   }
 
   template <class S> Handle<S> at(int index) {
-    DCHECK(index < length());
+    DCHECK_LT(index, length());
     return Arguments::at<S>(index);
   }