SqlStreamInput/Output use TransportVersion from a read-in Version constant. We need to remove the useage of `transportVersion` field
x-pack/plugin/ql/test-fixtures/src/main/java/org/elasticsearch/xpack/ql/TestNodes.java
public void add(TestNode node) {
        put(node.id(), node);
    }
    public List<TestNode> getNewNodes() {
        Version bwcVersion = getBWCVersion();
        return values().stream().filter(n -> n.version().after(bwcVersion)).collect(Collectors.toList());
    }
    public List<TestNode> getBWCNodes() {
        Version bwcVersion = getBWCVersion();
        return values().stream().filter(n -> n.version().equals(bwcVersion)).collect(Collectors.toList());
    }
    public Version getBWCVersion() {
        if (isEmpty()) {
            throw new IllegalStateException("no nodes available");
        }
        return Version.fromId(values().stream().mapToInt(node -> node.version().id).min().getAsInt());
    }
    @Override
    public String toString() {
        return "Nodes{" + values().stream().map(TestNode::toString).collect(Collectors.joining("\n")) + '}';
    }
}