Reserve element 0 in the references table for `dynamic`.

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

 // Copyright (c) 2015, 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.summary_test;
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_engine_io.dart';
 import 'package:analyzer/src/generated/source.dart';
@@ skipping 210 matching lines @@
       bool allowTypeParameters: false,
       PrelinkedReferenceKind expectedKind: PrelinkedReferenceKind.classOrEnum,
       int expectedTargetUnit: 0,
       PrelinkedUnit sourceUnit}) {
     sourceUnit ??= definingUnit;
     expect(typeRef, new isInstanceOf<UnlinkedTypeRef>());
     expect(typeRef.paramReference, 0);
     int index = typeRef.reference;
     UnlinkedReference reference = sourceUnit.unlinked.references[index];
     PrelinkedReference referenceResolution = sourceUnit.references[index];
+    if (index == 0) {
+      // Index 0 is reserved for "dynamic".
+      expect(reference.name, isEmpty);
+      expect(reference.prefix, 0);
+    }
     if (absoluteUri == null) {
       expect(referenceResolution.dependency, 0);
     } else {
       checkDependency(referenceResolution.dependency, absoluteUri, relativeUri);
     }
     if (!allowTypeParameters) {
       expect(typeRef.typeArguments, isEmpty);
     }
     if (expectedName == null) {
       expect(reference.name, isEmpty);
@@ skipping 1727 matching lines @@
         serializeClassText('class C { static int i; }').fields[0];
     expect(variable.isStatic, isTrue);
   }
 
   test_variable_type() {
     UnlinkedVariable variable =
         serializeVariableText('int i;', variableName: 'i');
     checkTypeRef(variable.type, 'dart:core', 'dart:core', 'int');
   }
 }