LU-16529 test: verify the grant > 0 before test

LU-16529 test: verify the grant > 0 before test

In the test 84 in sanity-quota, the grant should be larger than 0
after the dd complete, this patch adds check for it and forces the
quota to be re-integrated during the check.

Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Change-Id: I9cddcf0c4afc12a11f3535792262ebb35a1e480e
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50799
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Sergey Cheremencev <scherementsev@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>