[automerger skipped] Add TestNetworkTracker to test utils. am: bc5ce1bfc8 -s ours am: 75f1022e00 -s ours

am skip reason: Change-Id I6f8d1e36670c46ebcbca01e0a64ce579bcdcc1f9 with SHA-1 bc5ce1bfc8 is in history

Change-Id: I98566dae4fe7676d1976edcda95c7c04c9f440ae