LU-9560 tests: sanity test_801a sleeps more time

LU-9560 tests: sanity test_801a sleeps more time

If the barrier_freeze thread sleep time is too short, then
it is possible that before the barrier_stat thread scheduled,
the barrier_freeze thread has gone through phase "freezing_p1",
that will cause test failure.

This patch makes the barrier_freeze thread to sleep more long
time, then the barrier_stat thread can check its status properly.

Test-Parameters: trivial
Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Iebbc05a1d86553b484bd7093f147e5ac4b58e199
Reviewed-on: https://review.whamcloud.com/27288
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>