Observatory: remove unused imports

runtime/observatory/tests/service/issue_27238_test.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.
 // VMOptions=--error_on_bad_type --error_on_bad_override  --verbose_debug
 
-import 'package:observatory/service_io.dart';
 import 'service_test_common.dart';
 import 'dart:async';
 import 'test_helper.dart';
 import 'dart:developer';
 
-const int LINE_A = 20;
-const int LINE_B = 23;
-const int LINE_C = 24;
-const int LINE_D = 26;
-const int LINE_E = 27;
+const int LINE_A = 19;
+const int LINE_B = 22;
+const int LINE_C = 23;
+const int LINE_D = 25;
+const int LINE_E = 26;
 
 testMain() async {
   debugger();
   Future future1 = new Future.value();  // LINE_A.
   Future future2 = new Future.value();
 
   await future1;  // LINE_B.
   await future2;  // LINE_C.
 
   print('foo1'); // LINE_D.
@@ skipping 11 matching lines @@
   smartNext,
   hasStoppedAtBreakpoint,
   stoppedAtLine(LINE_C),
   smartNext,
   hasStoppedAtBreakpoint,
   stoppedAtLine(LINE_D),
   resumeIsolate,
 ];
 
 main(args) => runIsolateTests(args, tests, testeeConcurrent: testMain);