Observatory: remove unused imports

runtime/observatory/tests/service/issue_27238_test.dart

Index: runtime/observatory/tests/service/issue_27238_test.dart
diff --git a/runtime/observatory/tests/service/issue_27238_test.dart b/runtime/observatory/tests/service/issue_27238_test.dart
index 07cf3357b36b59b02940331b1d69265ae6b786e7..77302ae82864ddb21a81bb4a233a410bd1e92017 100644
--- a/runtime/observatory/tests/service/issue_27238_test.dart
+++ b/runtime/observatory/tests/service/issue_27238_test.dart
@@ -3,17 +3,16 @@
 // 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();