Implement _SameResolutionValidator as AstComparator.

pkg/analyzer/test/generated/incremental_resolver_test.dart

 // Copyright (c) 2014, 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.generated.incremental_resolver_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/context/cache.dart';
@@ skipping 3538 matching lines @@
   static CompilationUnit _parseUnit(String code) {
     var errorListener = new BooleanErrorListener();
     var reader = new CharSequenceReader(code);
     var scanner = new Scanner(null, reader, errorListener);
     var token = scanner.tokenize();
     var parser = new Parser(null, errorListener);
     return parser.parseCompilationUnit(token);
   }
 
   static void _shiftTokens(Token token, int afterOffset, int delta) {
-    while (token.type != TokenType.EOF) {
-      if (token.offset >= afterOffset) {
+    while (true) {
+      if (token.offset > afterOffset) {
         token.applyDelta(delta);
       }
+      if (token.type == TokenType.EOF) {
+        break;
+      }
       token = token.next;
     }
   }
 }
 
 /**
  * The test for [poorMansIncrementalResolution] function and its integration
  * into [AnalysisContext].
  */
 @reflectiveTest
@@ skipping 1739 matching lines @@
   void logException(Object exception, [Object stackTrace]) {
     lastException = exception;
     lastStackTrace = stackTrace;
   }
 
   @override
   logging.LoggingTimer startTimer() {
     return new logging.LoggingTimer(this);
   }
 }