run services tests on the Web (#41806)

dev/bots/test.dart

@@ -435,13 +435,12 @@ Future<void> _runTests() async {
 }
 
 Future<void> _runWebTests() async {
-  // TODO(yjbanov): re-enable when web test cirrus flakiness is resolved
   await _runFlutterWebTest(path.join(flutterRoot, 'packages', 'flutter'), tests: <String>[
     'test/foundation/',
     'test/physics/',
+    'test/services/',
     // TODO(yjbanov): re-enable when flakiness is resolved
     // 'test/rendering/',
-    // 'test/services/',
     // 'test/painting/',
     // 'test/scheduler/',
     // 'test/semantics/',

packages/flutter/test/services/channel_buffers_test.dart

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// TODO(yjbanov): enable Web when https://github.com/flutter/engine/pull/12747 rolls into the framework.
+@TestOn('!chrome')
+
 import 'dart:convert';
 import 'dart:typed_data';
 import 'dart:ui' as ui;
@@ -39,7 +42,7 @@ void main() {
     bool didDrainData = false;
     binding.defaultBinaryMessenger.setMessageHandler(channel, (ByteData message) async {
       expect(_getString(message), payload);
-      didDrainData= true;
+      didDrainData = true;
       return null;
     });
     // Flush the event queue.