- Update tests to make sure they recerefence invalid code.

dart/tests/language/src/Prefix15NegativeTest.dart

Index: dart/tests/language/src/Prefix15NegativeTest.dart
===================================================================
--- dart/tests/language/src/Prefix15NegativeTest.dart	(revision 1146)
+++ dart/tests/language/src/Prefix15NegativeTest.dart	(working copy)
@@ -7,10 +7,11 @@
 #library("Prefix15NegativeTest.dart");
 #import("library12.dart", prefix:"lib12");
 
-class myClass implements lib12.Library13 {
+class MyClass implements lib12.Library13 {
   myClass(int this.fld) : super(0);
   int fld;
 }
 
 main() {
+  new MyClass();
 }