Removed warnings from service tests

runtime/observatory/tests/service/evaluate_in_async_star_activation_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.
 
-import 'dart:async';
 import 'dart:developer';
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'service_test_common.dart';
 import 'test_helper.dart';
 
 generator() async* {
   var x = 3;
   var y = 4;
   debugger();
   yield y;
   var z = x + y;
   debugger();
   yield z;
 }
 
 testFunction() async {
   await for (var ignored in generator());
 }
 
 var tests = [
 
 hasStoppedAtBreakpoint,
 
 (Isolate isolate) async {
   // Make sure we are in the right place.
   var stack = await isolate.getStack();
   var topFrame = 0;
   expect(stack.type, equals('Stack'));
-  expect(await stack['frames'][topFrame].location.getLine(), 16);
+  expect(await stack['frames'][topFrame].location.getLine(), 15);
 
   var result = await isolate.evalFrame(topFrame, "x");
   print(result);
   expect(result.valueAsString, equals("3"));
 },
 
 resumeIsolate,
 
 hasStoppedAtBreakpoint,
 
 (Isolate isolate) async {
   // Make sure we are in the right place.
   var stack = await isolate.getStack();
   var topFrame = 0;
   expect(stack.type, equals('Stack'));
-  expect(await stack['frames'][topFrame].location.getLine(), 19);
+  expect(await stack['frames'][topFrame].location.getLine(), 18);
 
   var result = await isolate.evalFrame(topFrame, "z");
   print(result);
   expect(result.valueAsString, equals("7"));
 },
 
 resumeIsolate,
 
 ];
 
 main(args) => runIsolateTests(args, tests, testeeConcurrent: testFunction);