Intent of nil_principal_falls_back_to_task_queue_prefix, includeSystemWorkers=false_excludes_system_workers

All 2 exact tests in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 2 tests
- server/ 2 tests
  - service/ 2 tests
    
    matching/ 2 tests
    
    workers/ 2 tests
    
    TestFilterWorkersExcludesSystemWorkers/ 1 test
    
    go.temporal.io/server/service/matching/workers/TestFilterWorkersExcludesSystemWorkers/includeSystemWorkers=false_excludes_system_workers Introduced here
    
    TestIsSystemWorker/ 1 test
    
    go.temporal.io/server/service/matching/workers/TestIsSystemWorker/nil_principal_falls_back_to_task_queue_prefix Introduced here