Intent of TestSetTaskKeys_ScheduledTasks

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
    
    history/ 2 tests
    
    shard/ 2 tests
    
    TestTaskKeyGeneratorSuite/ 1 test
    
    go.temporal.io/server/service/history/shard/TestTaskKeyGeneratorSuite/TestSetTaskKeys_ScheduledTasks Introduced here
    
    TestTaskKeyManagerSuite/ 1 test
    
    go.temporal.io/server/service/history/shard/TestTaskKeyManagerSuite/TestGetExclusiveReaderHighWatermark_WithPendingTask Inherited TestGetExclusiveReaderHighWatermark_WithPendingTask