enable --dump-info with the --fast-startup emitter

pkg/compiler/lib/src/io/code_output.dart

 // Copyright (c) 2012, 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.code_output;
 
 import 'dart:async';
 
 import 'source_information.dart';
 
@@ skipping 21 matching lines @@
   ///
   /// If the output is closed, a [StateError] is thrown.
   void add(String text);
 
   /// Adds the content of [buffer] to the output and adds its markers to
   /// [markers].
   ///
   /// If the output is closed, a [StateError] is thrown.
   void addBuffer(CodeBuffer buffer);
 
-  /// Returns the number of characters currently write to this output.
+  /// Returns the number of characters currently written to this output.
   int get length;
 
   /// Returns `true` if this output has been closed.
   bool get isClosed;
 
   /// Closes the output. Further writes will cause a [StateError].
   void close();
 }
 
 abstract class AbstractCodeOutput extends CodeOutput {
@@ skipping 92 matching lines @@
   }
 
   void close() {
     output.close();
     super.close();
     if (_listeners != null) {
       _listeners.forEach((listener) => listener.onDone(length));
     }
   }
 }