Intent of valid_when_scheduled_and_attempt_matches, invalid_when_scheduled_but_attempt_mismatches

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
  - chasm/ 2 tests
    
    lib/ 2 tests
    
    nexusoperation/ 2 tests
    
    TestCancellationInvocationTaskHandler_Validate/ 2 tests
    
    go.temporal.io/server/chasm/lib/nexusoperation/TestCancellationInvocationTaskHandler_Validate/invalid_when_scheduled_but_attempt_mismatches Introduced here
    
    go.temporal.io/server/chasm/lib/nexusoperation/TestCancellationInvocationTaskHandler_Validate/valid_when_scheduled_and_attempt_matches Introduced here