Intent of TestSentinelIdleTask_Validate_InvalidAfterClosed

All 1 exact test in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 1 test
- server/ 1 test
  - chasm/ 1 test
    
    lib/ 1 test
    
    scheduler/ 1 test
    
    go.temporal.io/server/chasm/lib/scheduler/TestSentinelIdleTask_Validate_InvalidAfterClosed Introduced here