Add method to reload `AppCache`

[Vlastimil Zíma]

Some tests require test application, e.g. ​proxy_model_inheritance. Adding test application is simple, but removing is not so simple.

I propose addition of new method which would clean caches and repopulate them.

def reload(self):
    # Clean cache
    self._get_models_cache.clear()
    self.handled.clear()
    # Mark cache is empty
    self.loaded = False
    # Populate cache again
    self._populate()

[Jacob]

I'm deeply skeptical that this'll actually work. The real answer here is the app-refactor work, which is still ongoing; this is effectively a duplicate of that.

[Vlastimil Zíma]

Is there a ticket for that? I can't find any relevant one.

[Aymeric Augustin]

That's #3591.

[Vlastimil Zíma]

Thanks