Regression: Singleton property lookup fails

The change https://codereview.qt-project.org/#/c/249101/ introduces a bug when accessing singleton properties, if there a multiple singletons which have properties with the same name.

The problem is, that if you create multiple instances of a component and pass in different singletons, the component accesses the cached properties of another singleton.

In the example that I have, you can see that if you have two instances of a component and two different singletons, it fails to properly display the values.