Add tests for pause, resume and stop keepalives. am: 7c792c8d01

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/23668884

Change-Id: I0b18c766193b5b79035907596ccac41edce805ea
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>