Merge branch 'stable-3.9'

* stable-3.9:
  Use index on ChangeNotes which supports local and imported changes
  Consume global-refdb from source
  Add global-refdb libModule to high-available Docker test
  Remove syslog-sidecar volume in Docker test
  Bump Gerrit to v3.7.7 in Docker tests
  Fix docker-based tests
  Remove `@NoHttpd` from IT tests that interact with Gerrit Rest API

Change-Id: Id41ffa3d89e16c2a6a4446bad896d3672ac1bcf0