Add testTetherClatBpfOffloadUdp to TetheringTest

Add a new test case to TetheringTest. It verifies upstream and
downstream UDP packets are actually processed by Clatd's BPF offload.

Bug: 285124667
Test: atest TetheringIntegrationTests
Change-Id: I2f0c3953499af7a701c1b7e72830d502efbd31a1
1 file changed