Fix warnings_checker.dart handling of multitests

tests/language_strong/sync_generator2_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.
 
 // Simple test program for sync* generator functions.
 
 import "package:expect/expect.dart";
 import "dart:async";
 
 var sync = "topLevelSync";
 var async = "topLevelAync";
 var await = "topLevelAwait";
 var yield = "topLevelYield";
 
 test01() sync* {
-  var yield = 0; // /// 01: compile-time error
-  var await = 0; // /// 02: compile-time error
-  var async = 0; // /// 03: compile-time error
-  bool yield() => false; /// 04: compile-time error
-  bool await() => false; /// 05: compile-time error
-  bool async() => false; /// 06: compile-time error
+  var yield = 0; // //# 01: compile-time error
+  var await = 0; // //# 02: compile-time error
+  var async = 0; // //# 03: compile-time error
+  bool yield() => false; //# 04: compile-time error
+  bool await() => false; //# 05: compile-time error
+  bool async() => false; //# 06: compile-time error
 
   var x1 = sync;
-  var x2 = async; // /// 07: compile-time error
-  var x3 = await; // /// 08: compile-time error
-  var x4 = await 55; // /// 09: compile-time error
-  var x4 = yield; // /// 10: compile-time error
+  var x2 = async; // //# 07: compile-time error
+  var x3 = await; // //# 08: compile-time error
+  var x4 = await 55; // //# 09: compile-time error
+  var x4 = yield; // //# 10: compile-time error
 
   var stream = new Stream.fromIterable([1, 2, 3]);
-  await for (var e in stream) print(e); //  /// 11: compile-time error
+  await for (var e in stream) print(e); //  //# 11: compile-time error
 }
 
 test02() sync* {
   yield 12321;
-  return null; // /// 20: compile-time error
+  return null; // //# 20: compile-time error
 }
 
-test03() sync* => null; //  /// 30: compile-time error
+test03() sync* => null; //  //# 30: compile-time error
 
-get test04 sync* => null; // /// 40: compile-time error
-set test04(a) sync* { print(a); } // /// 41: compile-time error
+get test04 sync* => null; // //# 40: compile-time error
+set test04(a) sync* { print(a); } // //# 41: compile-time error
 
 class K {
-  K() sync* {}; // /// 50: compile-time error
+  K() sync* {}; // //# 50: compile-time error
   get nix sync* { }
-  get garnix sync* => null; // /// 51: compile-time error
-  set etwas(var z) sync* { } // /// 52: compile-time error
+  get garnix sync* => null; // //# 51: compile-time error
+  set etwas(var z) sync* { } // //# 52: compile-time error
   sync() sync* {
     yield sync;  // Yields a tear-off of the sync() method.
   }
 }
 
 main() {
   var x;
   x = test01();
   Expect.equals("()", x.toString());
   x = test02();
-  test03(); /// 30: continued
+  test03(); //# 30: continued
   Expect.equals("(12321)", x.toString());
-  x = test04; // /// 40: continued
-  test04 = x; // /// 41: continued
+  x = test04; // //# 40: continued
+  test04 = x; // //# 41: continued
   x = new K();
-  print(x.garnix); /// 51: continued
-  x.etwas = null; /// 52: continued
+  print(x.garnix); //# 51: continued
+  x.etwas = null; //# 52: continued
   print(x.sync().toList());
   Expect.equals(1, x.sync().length);
 //  Expect.isTrue(x.sync().single is Function);
 }