destroyed QQuickItems can be left in the dirty list

I haven't been able to track down the change that has caused this, but since updating to 5.4, I am getting crashes stemming from deleted QQuickItems still being present in the dirty list. The crash occurs in QQuickItemPrivate::addToDirtyList() when it calls QQuickItemPrivate::get(nextDirtyItem) on the deleted item. I did not see this crash in 5.3.1, but maybe I was just getting lucky.

I would think that a good fix would be to call d->removeFromDirtyList() at the end of ~QQuickItem(), and I'm happy to submit a patch to do that, but I wanted to verify that fix with someone who is more familiar with this code. Please let me know if you'd like me to submit a patch.

Thanks,
Alex