Fix Windows paths in complex_reload_test

runtime/observatory/tests/service/complex_reload_test.dart

 // Copyright (c) 2016, 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.
 // VMOptions=--error_on_bad_type --error_on_bad_override
 
 import 'test_helper.dart';
 import 'dart:async';
 import 'dart:developer';
 import 'dart:isolate' as I;
 import 'dart:io';
 import 'service_test_common.dart';
 import 'package:observatory/service.dart';
 import 'package:unittest/unittest.dart';
 
 testMain() async {
   debugger();  // Stop here.
   // Spawn the child isolate.
   I.Isolate isolate =
       await I.Isolate.spawnUri(Uri.parse('complex_reload/v1/main.dart'),
                                [],
                                null);
   print(isolate);
   debugger();
 }
 
 // Directory that we are running in.
-String directory = Platform.pathSeparator +
+String directory = (Platform.isWindows ? '' : Platform.pathSeparator) +
     Platform.script.pathSegments.sublist(
         0,
         Platform.script.pathSegments.length - 1).join(Platform.pathSeparator);
 
 Future<String> invokeTest(Isolate isolate) async {
   await isolate.reload();
   Library lib = isolate.rootLibrary;
   await lib.load();
   Instance result = await lib.evaluate('test()');
   expect(result.isString, isTrue);
@@ skipping 38 matching lines @@
     );
     expect(response['success'], isTrue);
 
     // Invoke test in v3.
     String v3 = await invokeTest(slaveIsolate);
     expect(v3, 'cabbage');
   }
 ];
 
 main(args) => runIsolateTests(args, tests, testeeConcurrent: testMain);