Calling Object.getOwnPropertyDescriptor() on a QScriptClass property returns a data descriptor

Arguably it should return an accessor descriptor, since the property is implemented using getter/setter functions.
Creating the data descriptor means that we have to call the getter itself. Since we use getOwnPropertyDescriptor() to implement QScriptValue::propertyFlags(), this call is unexpected and unnecessary.

In order to return an accessor descriptor, we would have to create function objects that bind the property name (since the QScriptClass methods themselves are catch-all accessors). Is it worth it...?