Interpreter: initialize arity fields of AP_NOUPDs
AP_NOUPD entry code doesn't use the arity field, but not initializing this field confuses printers/debuggers, and also makes testing harder as the field's value changes randomly.
AP_NOUPD entry code doesn't use the arity field, but not initializing this field confuses printers/debuggers, and also makes testing harder as the field's value changes randomly.