[Security Solution] Test plan for query fields diff algorithm (#192529

)

## Summary

Related ticket: #187658

Adds test plan for diff algorithm for arrays of scalar values
implemented here: #190179


### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)