Fix warnings_checker.dart handling of multitests

tests/language/keyword_type_expression_test.dart

Index: tests/language/keyword_type_expression_test.dart
diff --git a/tests/language/keyword_type_expression_test.dart b/tests/language/keyword_type_expression_test.dart
index 6edea2ced72e64c5e40d96c36cbd874e75c17963..e375c17d4b3dc462c3f2066a7734e0c335246750 100644
--- a/tests/language/keyword_type_expression_test.dart
+++ b/tests/language/keyword_type_expression_test.dart
@@ -5,11 +5,11 @@
 // Test that a keyword can't be used as type.  Serves as regression test for
 // crashes in dart2js.
 
-in greeting = "fisk"; // /// 01: compile-time error
+in greeting = "fisk"; // //# 01: compile-time error
 
 main(
-in greeting // /// 02: compile-time error
+in greeting // //# 02: compile-time error
 ) {
-  in greeting = "fisk"; // /// 03: compile-time error
-  print(greeting); // /// 01: continued
+  in greeting = "fisk"; // //# 03: compile-time error
+  print(greeting); // //# 01: continued
 }