Add expectAsyncX and expectAsyncUntilX methods, and deprecate the old methods.

test/runner/configuration/top_level_test.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.
 
 @TestOn("vm")
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:path/path.dart' as p;
@@ skipping 45 matching lines @@
       "",
       startsWith("Observatory URL: "),
       startsWith("Remote debugger URL: "),
       "The test runner is paused. Open the remote debugger or the Observatory "
           "and set breakpoints. Once",
       "you're finished, return to this terminal and press Enter."
     ]));
 
     schedule(() async {
       var nextLineFired = false;
-      test.stdout.next().then(expectAsync((line) {
+      test.stdout.next().then(expectAsync1((line) {
         expect(line, contains("+0: success"));
         nextLineFired = true;
       }));
 
       // Wait a little bit to be sure that the tests don't start running without
       // our input.
       await new Future.delayed(new Duration(seconds: 2));
       expect(nextLineFired, isFalse);
     });
 
@@ skipping 477 matching lines @@
           test("failure", () => throw "oh no");
         }
       """)
     ]).create();
 
     var test = runTest([]);
     test.stdout.expect(consumeThrough(contains('All tests passed!')));
     test.shouldExit(0);
   });
 }