Update remaining usages of Completer.completeException.

tests/lib/async/future_test.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 future_test;
 
 import 'dart:async';
 import 'dart:isolate';
 
 testImmediate() {
@@ skipping 83 matching lines @@
   var port = new ReceivePort();
   future
       .then((v) { throw "Value not expected"; })
       .catchError((e) {
         Expect.equals(e.error, ex);
         port.close();
       }, test: (e) => e == ex);
   completer.completeError(ex);
 }
 
-testExceptionNoSuccessListeners() {
-  final completer = new Completer<int>();
-  final future = completer.future;
-  final ex = new Exception();
-  completer.completeException(ex); // future.then is not called, so no exception
-}
-
 testExceptionHandler() {
   final completer = new Completer<int>();
   final future = completer.future;
   final ex = new Exception();
 
   var ex2;
   var done = future.catchError((e) { ex2 = e.error; });
   completer.completeError(ex);
 
   var port = new ReceivePort();
@@ skipping 247 matching lines @@
   testFutureAsStreamCompleteImmediate();
   testFutureAsStreamCompleteErrorAfter();
   testFutureAsStreamWrapper();
 
   testFutureWhenCompleteValue();
   testFutureWhenCompleteError();
   testFutureWhenCompleteValueNewError();
   testFutureWhenCompleteErrorNewError();
 }