private int numberOfPreviouslyExpired() {
        return nodeRepository.nodes()
                .list(Node.State.parked)
                .nodeType(NodeType.host)
                .matching(this::parkedByProvisionedExpirer)
                .not().deprovisioning()
                .size();
    }
This moves nodes of type {@link NodeType#host} from provisioned to parked if they have been in provisioned too long.
Parked hosts are deprovisioned as well, if too many hosts are being expired.

Only {@link NodeType#host} is moved because any number of nodes of that type can exist. Other node types such as
{@link NodeType#confighost} have a fixed number and thus cannot be replaced while the fixed number of nodes exist in
any state.

@author freva
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ProvisionedExpirer.java