LU-14645 tests: test lfs setdirstripe with '/$'

LU-14645 tests: test lfs setdirstripe with '/$'

This patch improves one of the lfs setdirstripe tests to
verify that dir name ending with '/' also works.

Test-Parameters: trivial mdscount=2 mdtcount=4 \
env=ONLY=24B testlist=sanity

Change-Id: I237d5a9ebad42cc0569aa1db487d0df147372316
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49463
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>