TF-2953 Set up Patrol tests

integration_test/base/base_scenario.dart

@@ -0,0 +1,9 @@
+import 'package:patrol/patrol.dart';
+
+abstract class BaseScenario {
+  final PatrolIntegrationTester $;
+
+  const BaseScenario(this.$);
+
+  Future<void> execute();
+}