Fix warnings_checker.dart handling of multitests

tests/language_strong/list_literal_syntax_test.dart

 // Copyright (c) 2012, 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 "package:expect/expect.dart";
 
 abstract class I {}
 
 void main() {
   var list;
   list = <int
-    I /// 00: compile-time error
-    , int /// 01: static type warning
+    I //# 00: compile-time error
+    , int //# 01: static type warning
     >[0];
   Expect.equals(1, list.length);
 
   list = <int
-    , int /// 02: static type warning
-    , int /// 02: continued
+    , int //# 02: static type warning
+    , int //# 02: continued
     >[0];
   Expect.equals(1, list.length);
 
   list = <int
-    , int /// 03: static type warning
-    , int /// 03: continued
-    , int /// 03: continued
+    , int //# 03: static type warning
+    , int //# 03: continued
+    , int //# 03: continued
     >[0];
   Expect.equals(1, list.length);
 
   list =
-    <> /// 04: compile-time error
+    <> //# 04: compile-time error
     [0];
   Expect.equals(1, list.length);
 
   list =
-    <<>> /// 05: compile-time error
+    <<>> //# 05: compile-time error
     [0];
   Expect.equals(1, list.length);
 
   list =
-    <<<>>> /// 06: compile-time error
+    <<<>>> //# 06: compile-time error
     [0];
   Expect.equals(1, list.length);
 
   list =
-    <[]> /// 07: compile-time error
+    <[]> //# 07: compile-time error
     [0];
   Expect.equals(1, list.length);
 
   list = <int>[<int>[<int>[1][0]][0]];
   Expect.equals(1, list.length);
   Expect.equals(1, list[0]);
 
   list = <int>[<List<int>>[[1]][0][0]];
   Expect.equals(1, list.length);
   Expect.equals(1, list[0]);
 }