Remove package imports from itself.

pkg/front_end/lib/src/fasta/source/scope_listener.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 fasta.scope_listener;
 
-import 'package:front_end/src/fasta/scanner/token.dart' show Token;
+import '../scanner/token.dart' show Token;
 
 import 'unhandled_listener.dart' show NullValue, UnhandledListener;
 
 import '../builder/scope.dart' show Scope;
 
 export '../builder/scope.dart' show Scope;
 
 export 'unhandled_listener.dart' show NullValue, Unhandled;
 
 enum JumpTargetKind {
@@ skipping 178 matching lines @@
   }
 
   @override
   void endElseStatement(Token token) {
     debugEvent("endElseStatement");
     var body = pop();
     exitLocalScope();
     push(body);
   }
 }