Move TapPacketReader into EthernetTestInterface am: d0d2cb32a9

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3189183

Change-Id: I1391fdc7148209d7c76b0cec5efa19ccd60b3f08
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>