ExecOnDevice runs the desired command on the device.

GetAdbPorts picks unused ports for the adb_port, adb_server_port and emulator_port.

KillEmu kills the emulator identified by adbPort.

PickUnusedPort returns the first unused port that it finds.

RunfilesRoot returns the path to the test runfiles dir.

SetupEmu starts up the emulator and returns the path to where is running.