LU-13440 utils: update sanity 413a, 413b and 413c

LU-13440 utils: update sanity 413a, 413b and 413c

In sanity test 413a,413b and 413c, create "qos" directory on most
full directory, so that its subdirectories won't be created on the
same MDT.

Lustre-change: https://review.whamcloud.com/43530
Lustre-commit: 1dbe63301b8c5cb7f7d0fe9960cafd3cd0e45534

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Change-Id: Ia8061ee48ac219e6948d667269c3ad80f6198401
Reviewed-on: https://review.whamcloud.com/44542
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>