8068578: test/java/io/Serializable/subclassGC/SubclassGC.java assumes app class loader is a URLClassLoader
Reviewed-by: alanb
grant {
permission java.lang.RuntimePermission "createClassLoader";
permission java.lang.RuntimePermission "getClassLoader";
permission java.util.PropertyPermission "test.classes", "read";
permission java.io.FilePermission "<<ALL FILES>>", "read";
};