Intent of includes_system_workers_when_requested

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
    
    TestRegistryImpl_CountWorkersExcludesSystemWorkers/ 2 tests
    
    go.temporal.io/server/service/matching/workers/TestRegistryImpl_CountWorkersExcludesSystemWorkers/excludes_system_workers_by_default Inherited excludes_system_workers_by_default
    
    go.temporal.io/server/service/matching/workers/TestRegistryImpl_CountWorkersExcludesSystemWorkers/includes_system_workers_when_requested Introduced here