Fix warnings_checker.dart handling of multitests

tests/compiler/dart2js_extra/compile_time_constant4_test.dart

Index: tests/compiler/dart2js_extra/compile_time_constant4_test.dart
diff --git a/tests/compiler/dart2js_extra/compile_time_constant4_test.dart b/tests/compiler/dart2js_extra/compile_time_constant4_test.dart
index 5008b78a790fad41b1e56ea449a52b6fc72a35a6..4effc854e141326acf42049f54904b4f578c16ab 100644
--- a/tests/compiler/dart2js_extra/compile_time_constant4_test.dart
+++ b/tests/compiler/dart2js_extra/compile_time_constant4_test.dart
@@ -10,22 +10,22 @@ const g1 = x
   + "bar"
 ;
 const g2 = x
-  + null //  /// 01: compile-time error
+  + null //  //# 01: compile-time error
 ;
 const g3 = x
-  + 499 //  /// 02: compile-time error
+  + 499 //  //# 02: compile-time error
 ;
 const g4 = x
-  + 3.3 //  /// 03: compile-time error
+  + 3.3 //  //# 03: compile-time error
 ;
 const g5 = x
-  + true //  /// 04: compile-time error
+  + true //  //# 04: compile-time error
 ;
 const g6 = x
-  + false //  /// 05: compile-time error
+  + false //  //# 05: compile-time error
 ;
 const g7 = "foo"
-  + x[0] //  /// 06: compile-time error
+  + x[0] //  //# 06: compile-time error
 ;
 const g8 = 1
   + x.length