Fix warnings_checker.dart handling of multitests

tests/corelib_strong/iterable_return_type_test.dart

 // Copyright (c) 2013, 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.
 
 // Regression test for dart2js where [List.addAll] was not typed
 // correctly.
 
 import "package:expect/expect.dart";
 
 import 'dart:collection';
@@ skipping 45 matching lines @@
   testList(const <int>[]);
   testList(new List<int>.generate(0, (x) => x + 1));
   // Singleton lists.
   testList(<int>[1]);
   testList(new List<int>(1)..[0] = 1);
   testList(new List<int>()..add(1));
   testList(const <int>[1]);
   testList(new List<int>.generate(1, (x) => x + 1));
 
   // Typed lists.
-  testList(new Uint8List(1)..[0] = 1); //  /// 01: ok
-  testList(new Int8List(1)..[0] = 1); //   /// 01: continued
-  testList(new Uint16List(1)..[0] = 1); // /// 01: continued
-  testList(new Int16List(1)..[0] = 1); //  /// 01: continued
-  testList(new Uint32List(1)..[0] = 1); // /// 01: continued
-  testList(new Int32List(1)..[0] = 1); //  /// 01: continued
-  testList(new Uint64List(1)..[0] = 1); // /// 02: ok
-  testList(new Int64List(1)..[0] = 1); //  /// 02: continued
+  testList(new Uint8List(1)..[0] = 1); //  //# 01: ok
+  testList(new Int8List(1)..[0] = 1); //   //# 01: continued
+  testList(new Uint16List(1)..[0] = 1); // //# 01: continued
+  testList(new Int16List(1)..[0] = 1); //  //# 01: continued
+  testList(new Uint32List(1)..[0] = 1); // //# 01: continued
+  testList(new Int32List(1)..[0] = 1); //  //# 01: continued
+  testList(new Uint64List(1)..[0] = 1); // //# 02: ok
+  testList(new Int64List(1)..[0] = 1); //  //# 02: continued
 
   testIterable(new Set<int>()..add(1));
   testIterable(new HashSet<int>()..add(1));
   testIterable(new LinkedHashSet<int>()..add(1));
   testIterable(new SplayTreeSet<int>()..add(1));
 
   testIterable(new Queue<int>()..add(1));
   testIterable(new DoubleLinkedQueue<int>()..add(1));
   testIterable(new ListQueue<int>()..add(1));
 
   testMap(new Map<int,int>()..[1] = 1);
   testMap(new HashMap<int,int>()..[1] = 1);
   testMap(new LinkedHashMap<int,int>()..[1] = 1);
   testMap(new SplayTreeMap<int,int>()..[1] = 1);
   testMap(<int,int>{1:1});
   testMap(const <int,int>{1:1});
 }