Merge "TetheringTest: replace upstream change check by event callback" am: 119e5adc14 am: 550d3f8816

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2383985

Change-Id: I0febfcad018a1d193a2dea1a6c7c7ecf7738d57c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>