private int switchPriority(NodeCandidate other) {
        if (this.exclusiveSwitch && !other.exclusiveSwitch) return -1;
        if (other.exclusiveSwitch && !this.exclusiveSwitch) return 1;
        return 0;
    }
Returns the switch priority, based on switch exclusivity, of this compared to other
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/NodeCandidate.java