Eclipse JGit: Java implementation of Git 4.11.9

Bug Fixes

• 548716, Gerrit 11373 PackedBatchRefUpdate: reproduce racy atomic update, and fix it
• downported from stable-5.1
  • Delete unused FileTreeIteratorWithTimeControl
  • 548188 Fix RacyGitTests#testRacyGitDetection
  • 526111 Change RacyGitTests to create a racy git situation in a stable way

Build and Release Engineering

• Bazel: Update bazlets to the latest master revision