Depend on the goldens repo through git. (#25479)

It's easier to run the android_views integration test this way, without
needing to worry if we have a local clone of the goldens repo or not.

dev/integration_tests/android_views/pubspec.yaml

@@ -10,7 +10,9 @@ dependencies:
   path_provider: 0.4.1
   collection: 1.14.11
   assets_for_android_views:
-    path: ../../../bin/cache/pkg/goldens/dev/integration_tests/assets_for_android_views
+    git:
+      url: https://github.com/flutter/goldens.git
+      path: dev/integration_tests/assets_for_android_views
 
   async: 2.0.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   charcode: 1.1.2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
@@ -33,8 +35,6 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  flutter_goldens:
-    sdk: flutter
   test: 1.5.1
 
   analyzer: 0.33.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"

dev/integration_tests/android_views/test_driver/main_test.dart

@@ -5,17 +5,9 @@
 import 'dart:async';
 
 import 'package:flutter_driver/flutter_driver.dart';
-import 'package:flutter_goldens_client/client.dart';
 import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 
 Future<void> main() async {
-
-  setUpAll(() async {
-    print('Cloning goldens repository...');
-    final GoldensClient goldensClient = GoldensClient();
-    await goldensClient.prepare();
-  });
-
   test('MotionEvents recomposition', () async {
     final FlutterDriver driver = await FlutterDriver.connect();
     final String errorMessage = await driver.requestData('run test');