Handle redirects to unresolved redirects

tests/compiler/dart2js/serialization/test_data.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 dart2js.serialization_test_data;
 
 const List<Test> TESTS = const <Test>[
   const Test('Empty program', const {
     'main.dart': 'main() {}'
   }),
@@ skipping 92 matching lines @@
     'main.dart': r'''
 class Class implements Comparable<Class, Class> {
   int compareTo(other) => 0;
 }
 main() {
   print(new Class());
 }'''
   },
   expectedWarningCount: 1),
 
-  const Test('Impliment Comparable with incompatible parameter types', const {
+  const Test('Implement Comparable with incompatible parameter types', const {
     'main.dart': r'''
 class Class implements Comparable<Class> {
   int compareTo(String other) => 0;
 }
 main() {
   print(new Class().compareTo(null));
 }'''
   },
   expectedWarningCount: 1,
   expectedInfoCount: 1),
 
-  const Test('Impliment Comparable with incompatible parameter count', const {
+  const Test('Implement Comparable with incompatible parameter count', const {
     'main.dart': r'''
 class Class implements Comparable {
   bool compareTo(a, b) => true;
 }
 main() {
   print(new Class().compareTo(null, null));
 }'''
   },
   expectedWarningCount: 1,
   expectedInfoCount: 1),
@@ skipping 453 matching lines @@
   const Test(
       this.name,
       this.sourceFiles,
       {this.preserializedSourceFiles,
       this.unserializedSourceFiles,
       this.expectedErrorCount: 0,
       this.expectedWarningCount: 0,
       this.expectedHintCount: 0,
       this.expectedInfoCount: 0});
 }