Create read only handles for empty_array and sentinel objects

vm/class_finalizer_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
 #include "vm/symbols.h"
 #include "vm/unit_test.h"
 
 namespace dart {
 
 
 static RawClass* CreateTestClass(const char* name) {
-  const Array& empty_array = Array::Handle(Object::empty_array());
   const String& class_name = String::Handle(Symbols::New(name));
   const Script& script = Script::Handle();
   const Class& cls =
       Class::Handle(Class::New(class_name, script, Scanner::kDummyTokenIndex));
-  cls.set_interfaces(empty_array);
-  cls.SetFunctions(empty_array);
-  cls.SetFields(empty_array);
+  cls.set_interfaces(Object::empty_array());
+  cls.SetFunctions(Object::empty_array());
+  cls.SetFields(Object::empty_array());
   return cls.raw();
 }
 
 
 TEST_CASE(ClassFinalizer) {
   Isolate* isolate = Isolate::Current();
   ObjectStore* object_store = isolate->object_store();
   const GrowableObjectArray& pending_classes =
       GrowableObjectArray::Handle(isolate, object_store->pending_classes());
   GrowableArray<const Class*> classes_1;
@@ skipping 65 matching lines @@
                            Scanner::kDummyTokenIndex));
   const TypeArguments& type_arguments = TypeArguments::Handle();
   rhb.set_super_type(Type::Handle(
       Type::New(Object::Handle(unresolved.raw()),
                 type_arguments,
                 Scanner::kDummyTokenIndex)));
   EXPECT(ClassFinalizer::FinalizePendingClasses());
 }
 
 }  // namespace dart