Add back tethering to mainline-postsubmit

Tethering was removed from mainline-postsubmit while Connectivity was
being added to it, but it can run in postsubmit again now.

If the runs are successful, it can be added to presubmit as well.

Ignore-AOSP-First: Partial revert of change that did not go to AOSP
Bug: 177290955
Test: TH needs to test postsubmit

Change-Id: I5d5dbccd8d14be573104947412a76578b2d7a6c1
1 file changed