Fix warnings_checker.dart handling of multitests

tests/language_strong/issue18628_2_test.dart

Index: tests/language_strong/issue18628_2_test.dart
diff --git a/tests/language_strong/issue18628_2_test.dart b/tests/language_strong/issue18628_2_test.dart
index a6e1cfd73e4d946f64babac1432f8118a4cb47e3..3232ea0fbae80bef8db919238cad1683e6df7742 100644
--- a/tests/language_strong/issue18628_2_test.dart
+++ b/tests/language_strong/issue18628_2_test.dart
@@ -12,9 +12,9 @@ class X<T extends Type> {}
 
 // This line is supposed to cause the warning; the other lines are
 // marked because they don't make sense when [Y] is not defined.
-class Y<U> extends X<U> {} /// 01: static type warning
+class Y<U> extends X<U> {} //# 01: static type warning
 
 main() {
-  X<Type> x = new X<Type>(); /// 01: static type warning
-  Y<Type> y = new Y<Type>(); /// 01: static type warning
+  X<Type> x = new X<Type>(); //# 01: static type warning
+  Y<Type> y = new Y<Type>(); //# 01: static type warning
 }