Fix warnings_checker.dart handling of multitests

tests/language_strong/cast_test.dart

Index: tests/language_strong/cast_test.dart
diff --git a/tests/language_strong/cast_test.dart b/tests/language_strong/cast_test.dart
index 4b49bf52b18fdc15dc0a2297642c36c13f38f605..c420a900c7c56288b12e7bddcd0c8a352c6529ba 100644
--- a/tests/language_strong/cast_test.dart
+++ b/tests/language_strong/cast_test.dart
@@ -35,42 +35,42 @@ main() {
   Expect.equals(42, (od as D).foo);
   Expect.equals(37, (od as D).bar);
   Expect.equals(37, ((od as C) as D).bar);
-  (oc as D).foo; // /// 01: runtime error
+  (oc as D).foo; // //# 01: runtime error
   (on as D).toString();
-  (on as D).foo; // /// 02: runtime error
-  (on as C).foo; // /// 03: runtime error
-  oc.foo; // /// 04: static type warning
-  od.foo; // /// 05: static type warning
+  (on as D).foo; // //# 02: runtime error
+  (on as C).foo; // //# 03: runtime error
+  oc.foo; // //# 04: static type warning
+  od.foo; // //# 05: static type warning
   (on as Object).toString();
   (oc as Object).toString();
   (od as Object).toString();
   (on as dynamic).toString();
-  (on as dynamic).foo; // /// 07: runtime error
+  (on as dynamic).foo; // //# 07: runtime error
   (oc as dynamic).foo;
   (od as dynamic).foo;
-  (oc as dynamic).bar; // /// 08: runtime error
+  (oc as dynamic).bar; // //# 08: runtime error
   (od as dynamic).bar;
   C c = oc as C;
   c = od as C;
   c = oc;
   D d = od as D;
-  d = oc as D; // /// 10: runtime error
+  d = oc as D; // //# 10: runtime error
   d = od;
 
   (ol as List)[0];
   (ol as List<int>)[0];
   (ol as dynamic)[0];
-  (ol as String).length; // /// 12: runtime error
+  (ol as String).length; // //# 12: runtime error
   int x = (ol as List<int>)[0];
   (ol as List<int>)[0] = (oi as int);
 
   (os as String).length;
   (os as dynamic).length;
-  (oi as String).length; // /// 13: runtime error
-  (os as List).length; // /// 14: runtime error
+  (oi as String).length; // //# 13: runtime error
+  (os as List).length; // //# 14: runtime error
 
   (oi as int) + 2;
-  (oi as List).length; // /// 15: runtime error
+  (oi as List).length; // //# 15: runtime error
 }