Merge "Add tethering IPv4 UDP forwarding test" am: 76bc75f0a2 am: 01c2b174bb

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1843121

Change-Id: I0365df5cc2eecbdf3cae5a20b63c34b3eaf460ad