Intent of blank-drops-old-data

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
  - common/ 1 test
    
    stats/ 1 test
    
    TestWindowedDigest/ 1 test
    
    go.temporal.io/server/common/stats/TestWindowedDigest/blank-drops-old-data Introduced here