Introduce {ConstantElementsPair} struct for type safety.

src/objects-printer.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/objects.h"
 
 #include <iomanip>
 #include <memory>
 
 #include "src/bootstrapper.h"
@@ skipping 1281 matching lines @@
   os << "\n";
 }
 
 void ContextExtension::ContextExtensionPrint(std::ostream& os) {  // NOLINT
   HeapObject::PrintHeader(os, "ContextExtension");
   os << "\n - scope_info: " << Brief(scope_info());
   os << "\n - extension: " << Brief(extension());
   os << "\n";
 }
 
+void ConstantElementsPair::ConstantElementsPairPrint(
+    std::ostream& os) {  // NOLINT
+  HeapObject::PrintHeader(os, "ConstantElementsPair");
+  os << "\n - elements_kind: " << static_cast<ElementsKind>(elements_kind());
+  os << "\n - constant_values: " << Brief(constant_values());
+  os << "\n";
+}
 
 void AccessorPair::AccessorPairPrint(std::ostream& os) {  // NOLINT
   HeapObject::PrintHeader(os, "AccessorPair");
   os << "\n - getter: " << Brief(getter());
   os << "\n - setter: " << Brief(setter());
   os << "\n";
 }
 
 
 void AccessCheckInfo::AccessCheckInfoPrint(std::ostream& os) {  // NOLINT
@@ skipping 361 matching lines @@
     printf("Not a transition array\n");
   } else {
     reinterpret_cast<i::TransitionArray*>(object)->Print();
   }
 }
 
 extern void _v8_internal_Print_StackTrace() {
   i::Isolate* isolate = i::Isolate::Current();
   isolate->PrintStack(stdout);
 }