Change hw6 to an unsolved version.

Signed-off-by: jmug <u.g.a.mariano@gmail.com>

hw6/hw5programs/tc_subtyping7.oat

@@ -14,7 +14,7 @@ B g((C) -> B f) {
   return f(c);
 }
 
-int program(string[] args) {
+int program(int argc, string[] args) {
   var b = g(f);
   return b.y;
 }