Fix warnings_checker.dart handling of multitests

tests/language_strong/assign_top_method_test.dart

Index: tests/language_strong/assign_top_method_test.dart
diff --git a/tests/language_strong/assign_top_method_test.dart b/tests/language_strong/assign_top_method_test.dart
index 32162b617284e65e15a67795b8d3c696572f5f0f..2fc8dd79cee2d281152a7754cd867b9335d8a96e 100644
--- a/tests/language_strong/assign_top_method_test.dart
+++ b/tests/language_strong/assign_top_method_test.dart
@@ -8,6 +8,6 @@ method() { return 0; }
 
 main() {
   // Illegal, can't change a top level method
-  Expect.throws(() { method = () { return 1; }; }, /// 01: static type warning
-                (e) => e is NoSuchMethodError); //   /// 01: continued
+  Expect.throws(() { method = () { return 1; }; }, //# 01: static type warning
+                (e) => e is NoSuchMethodError); //   //# 01: continued
 }