Move runDhcp to TetheringTester am: f320c21120 am: 97ac1a93fa am: ef9eb6af99

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1817921

Change-Id: I2fb3812afc40bc8c2d2e6d5286cc778c57da2701