Add an isEmpty convenience method to BpfMap. am: 77262cea76

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1560402

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I41ee1a37f33950d725c3349a149eaa6c6ce2c355
tree: cc5b9e0c2e9c21a3572416a681fbacb7584ef553
  1. framework/
  2. tests/
  3. Tethering/
  4. .gitignore
  5. OWNERS
  6. PREUPLOAD.cfg
  7. TEST_MAPPING