pkg/compiler: fix imports

pkg/compiler/lib/src/tokens/token.dart

 // Copyright (c) 2011, 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.tokens;
 
+import 'dart:collection' show HashSet;
 import 'dart:convert' show UTF8;
-import 'dart:collection' show HashSet;
 
 import '../common.dart';
 import '../util/util.dart' show computeHashCode;
-
 import 'keyword.dart' show Keyword;
 import 'precedence.dart' show PrecedenceInfo;
 import 'precedence_constants.dart' as Precedence show BAD_INPUT_INFO;
 import 'token_constants.dart' as Tokens show IDENTIFIER_TOKEN;
 
 /**
  * A token that doubles as a linked list.
  */
 abstract class Token implements Spannable {
   /**
@@ skipping 399 matching lines @@
       value == '<=' ||
       value == '<' ||
       value == '&' ||
       value == '^' ||
       value == '|';
 }
 
 bool isTernaryOperator(String value) => value == '[]=';
 
 bool isMinusOperator(String value) => value == '-';