Make type checking op quietly say no, so it can be safely used in a wider context.

Author: jnthn

src/ops/nqp.ops

@@ -1170,16 +1170,10 @@ make sure.
 inline op type_check(out INT, invar PMC, invar PMC) :base_core {
     PMC *val = decontainerize(interp, $2);
     PMC *type = decontainerize(interp, $3);
-    if (val->vtable->base_type == smo_id && type->vtable->base_type == smo_id) {
+    if (val->vtable->base_type == smo_id && type->vtable->base_type == smo_id)
         $1 = STABLE(val)->type_check(interp, val, type);
-    }
-    else if (type->vtable->base_type == smo_id) {
+    else
         $1 = 0;
-    }
-    else {
-        Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_INVALID_OPERATION,
-            "Can only use type_check to check against a SixModelObject");
-    }
 }