When using CONFIG_NO_HZ, rq->tick_timestamp is not updated every TICK_NSEC.
We check that the number of skipped ticks matches the clock jump seen in
__update_rq_clock().
Signed-off-by: NGuillaume Chazarain <guichaz@yahoo.fr>
Signed-off-by: NIngo Molnar <mingo@elte.hu>