Remove package imports from itself.

pkg/front_end/lib/src/fasta/source/stack_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.stack_listener;
 
-import 'package:front_end/src/fasta/parser.dart' show ErrorKind, Listener;
+import '../parser.dart' show ErrorKind, Listener;
 
-import 'package:front_end/src/fasta/parser/identifier_context.dart'
-    show IdentifierContext;
+import '../parser/identifier_context.dart' show IdentifierContext;
 
-import 'package:front_end/src/fasta/scanner.dart' show BeginGroupToken, Token;
+import '../scanner.dart' show BeginGroupToken, Token;
 
 import 'package:kernel/ast.dart' show AsyncMarker;
 
 import '../errors.dart' show inputError, internalError;
 
 import '../quote.dart' show unescapeString;
 
 import '../messages.dart' as messages;
 
 enum NullValue {
@@ skipping 262 matching lines @@
     list.setRange(0, arrayLength, array);
     return list;
   }
 
   void _grow() {
     final List newTable = new List(array.length * 2);
     newTable.setRange(0, array.length, array, 0);
     array = newTable;
   }
 }