Move runDhcp to TetheringTester am: f320c21120 am: 97ac1a93fa am: ef9eb6af99 am: becdc2a64d

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

Change-Id: Ib8d2bce7e49b5ee317ffff73e05aeb3fc4e6de53