Intent of emits_zero_when_nothing_is_buffered

All 3 exact tests in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 3 tests
- server/ 3 tests
  - chasm/ 3 tests
    
    lib/ 3 tests
    
    scheduler/ 3 tests
    
    TestSearchAttributes_BufferedStartsCount/ 2 tests
    
    go.temporal.io/server/chasm/lib/scheduler/TestSearchAttributes_BufferedStartsCount/counts_only_the_not-yet-started_backlog Inherited counts_only_the_not-yet-started_backlog
    
    go.temporal.io/server/chasm/lib/scheduler/TestSearchAttributes_BufferedStartsCount/emits_zero_when_nothing_is_buffered Introduced here
    
    TestSearchAttributes_RunningWorkflowCount/ 1 test
    
    go.temporal.io/server/chasm/lib/scheduler/TestSearchAttributes_RunningWorkflowCount/counts_only_started,_not-yet-completed_workflows Inherited counts_only_started,_not-yet-completed_workflows