Fix dartc break by removing re-export of fail from unittest; already in matcher.dart.

pkg/scheduled_test/lib/scheduled_test.dart

 // Copyright (c) 2013, 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.
 
 // TODO(nweiz): Add support for calling [schedule] while the schedule is already
 // running.
 // TODO(nweiz): Port the non-Pub-specific scheduled test libraries from Pub.
 /// A package for writing readable tests of asynchronous behavior.
 ///
 /// This package works by building up a queue of asynchronous tasks called a
@@ skipping 165 matching lines @@
 import 'dart:async';
 
 import 'package:unittest/unittest.dart' as unittest;
 
 import 'src/schedule.dart';
 import 'src/schedule_error.dart';
 import 'src/utils.dart';
 
 export 'package:unittest/matcher.dart';
 export 'package:unittest/unittest.dart' show
-    config, configure, Configuration, logMessage, expectThrow, fail;
+    config, configure, Configuration, logMessage, expectThrow;
 
 export 'src/schedule.dart';
 export 'src/schedule_error.dart';
 export 'src/task.dart';
 
 /// The [Schedule] for the current test. This is used to add new tasks and
 /// inspect the state of the schedule.
 ///
 /// This is `null` when there's no test currently running.
 Schedule get currentSchedule => _currentSchedule;
@@ skipping 136 matching lines @@
 ///
 /// The returned [Future] completes to the same value or error as [future].
 Future wrapFuture(Future future) {
   if (currentSchedule == null) {
     throw new StateError("Unexpected call to wrapFuture with no current "
         "schedule.");
   }
 
   return currentSchedule.wrapFuture(future);
 }