Add type info to fix analyzer failures for 1.23.0-dev.5.0

lib/src/runner/load_suite.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:async';
 
 import 'package:stack_trace/stack_trace.dart';
 
 import '../../test.dart';
 import '../backend/group.dart';
@@ skipping 48 matching lines @@
   Test get test => this.group.entries.single as Test;
 
   /// Creates a load suite named [name] on [platform].
   ///
   /// [body] may return either a [RunnerSuite] or a [Future] that completes to a
   /// [RunnerSuite]. Its return value is forwarded through [suite], although if
   /// it throws an error that will be forwarded through the suite's test.
   ///
   /// If the the load test is closed before [body] is complete, it will close
   /// the suite returned by [body] once it completes.
-  factory LoadSuite(String name, SuiteConfiguration config, body(),
+  factory LoadSuite(
+      String name, SuiteConfiguration config, FutureOr<RunnerSuite> body(),
       {String path, TestPlatform platform}) {
     var completer = new Completer<Pair<RunnerSuite, Zone>>.sync();
     return new LoadSuite._(name, config, () {
       var invoker = Invoker.current;
       invoker.addOutstandingCallback();
 
       invoke(() async {
         try {
           var suite = await body();
           if (completer.isCompleted) {
@@ skipping 96 matching lines @@
   }
 
   LoadSuite filter(bool callback(Test test)) {
     var filtered = this.group.filter(callback);
     if (filtered == null) filtered = new Group.root([], metadata: metadata);
     return new LoadSuite._filtered(this, filtered);
   }
 
   Future close() async {}
 }