public ApplicationInstance toApplicationNarrowedToHost(ApplicationInfo applicationInfo,
                                                           HostName hostname,
                                                           ServiceStatusProvider serviceStatusProvider) {
        var generator = new ApplicationInstanceGenerator(applicationInfo, zone);
        return generator.makeApplicationInstanceLimitedTo(hostname, serviceStatusProvider);
    }
Make an application instance that contains all services and clusters present on the host,
but lacking other services and hosts. This is an optimization over
{@link #toApplicationInstance(ApplicationInfo, ServiceStatusProvider)}.
service-monitor/src/main/java/com/yahoo/vespa/service/model/ModelGenerator.java