Fix warnings_checker.dart handling of multitests

tests/lib/mirrors/metadata_constructor_arguments_test.dart

Index: tests/lib/mirrors/metadata_constructor_arguments_test.dart
diff --git a/tests/lib/mirrors/metadata_constructor_arguments_test.dart b/tests/lib/mirrors/metadata_constructor_arguments_test.dart
index 03e1c24e6affadfa234d261138f6eb9a09f725ab..361d0677af2f0237c6fd6c10fd15e18b31084820 100644
--- a/tests/lib/mirrors/metadata_constructor_arguments_test.dart
+++ b/tests/lib/mirrors/metadata_constructor_arguments_test.dart
@@ -14,7 +14,7 @@ class Tag {
   const Tag({named}) : this.name = named;
 }
 
-@Tag(named: undefined) // /// 01: compile-time error
+@Tag(named: undefined) // //# 01: compile-time error
 class A {}
 
 @Tag(named: 'valid')
@@ -25,32 +25,32 @@ class C {
   static const STATIC_FIELD = 3;
 }
 
-@Tag(named: D.instanceMethod()) // /// 02: compile-time error
+@Tag(named: D.instanceMethod()) // //# 02: compile-time error
 class D {
   instanceMethod() {}
 }
 
-@Tag(named: instanceField) // /// 03: compile-time error
+@Tag(named: instanceField) // //# 03: compile-time error
 class E {
   var instanceField;
 }
 
-@Tag(named: F.nonConstStaticField) // /// 04: compile-time error
+@Tag(named: F.nonConstStaticField) // //# 04: compile-time error
 class F {
   static var nonConstStaticField = 6;
 }
 
-@Tag(named: instanceMethod) // /// 05: compile-time error
+@Tag(named: instanceMethod) // //# 05: compile-time error
 class G {
   instanceMethod() {}
 }
 
-@Tag(named: this) // /// 06: compile-time error
+@Tag(named: this) // //# 06: compile-time error
 class H {
   instanceMethod() {}
 }
 
-@Tag(named: super) // /// 07: compile-time error
+@Tag(named: super) // //# 07: compile-time error
 class I {
   instanceMethod() {}
 }