Fix for 'hasNoSupertype' for Object when summarize AST.

pkg/analyzer/test/src/summary/summarize_ast_test.dart

 // Copyright (c) 2016, 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.
 
 library analyzer.test.src.summary.summarize_ast_test;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
@@ skipping 90 matching lines @@
       if (unit == null) {
         if (!allowMissingFiles) {
           fail('Test referred to unknown unit $relativeUri');
         }
       } else {
         unlinkedUnits.add(unit);
       }
     }
   }
 
+  test_class_no_superclass() {
+    UnlinkedClass cls = serializeClassText('part of dart.core; class Object {}',
+        className: 'Object');
+    expect(cls.supertype, isNull);
+    expect(cls.hasNoSupertype, isTrue);
+  }
+
   CompilationUnit _parseText(String text) {
     CharSequenceReader reader = new CharSequenceReader(text);
     Scanner scanner =
         new Scanner(null, reader, AnalysisErrorListener.NULL_LISTENER);
     Token token = scanner.tokenize();
     Parser parser = new Parser(null, AnalysisErrorListener.NULL_LISTENER);
     parser.parseGenericMethods = true;
     return parser.parseCompilationUnit(token);
   }
 }