Restart b2g, waiting for the adb connection to become stable.

        :param timeout: Maximum time to wait for restart.
        :param wait_polling_interval: Interval at which to poll for device readiness.

def restart(self, wait=True, timeout=None, wait_polling_interval=None):
        """Restart b2g, waiting for the adb connection to become stable.

        :param timeout: Maximum time to wait for restart.
        :param wait_polling_interval: Interval at which to poll for device readiness.
        """
        self.stop(timeout=timeout)
        self.start(wait, timeout=timeout, wait_polling_interval=wait_polling_interval)