Remove flutter_view_ios__start_up.dart (#8978)

dev/devicelab/bin/tasks/flutter_view_ios__start_up.dart

-// Copyright 2017 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-import 'dart:async';
-
-import 'package:flutter_devicelab/tasks/perf_tests.dart';
-import 'package:flutter_devicelab/framework/adb.dart';
-import 'package:flutter_devicelab/framework/framework.dart';
-
-Future<Null> main() async {
-  deviceOperatingSystem = DeviceOperatingSystem.ios;
-  await task(createFlutterViewStartupTest());
-}

dev/devicelab/manifest.yaml

@@ -196,12 +196,6 @@ tasks:
     stage: devicelab_ios
     required_agent_capabilities: ["has-ios-device"]
 
-  flutter_view_ios__start_up:
-    description: >
-      Verifies that Flutter View can be used from an iOS project.
-    stage: devicelab_ios
-    required_agent_capabilities: ["has-ios-device"]
-
   # Tests running on Windows host
 
   flutter_gallery_win__build: