LU-14992 tests: add more mkdir_on_mdt0 calls

LU-14992 tests: add more mkdir_on_mdt0 calls

A previous patch changed some mkdir calls in test_133a to
mkdir_on_mdt0. This allows stats collected from mdt0 to
reflect the mkdir.

However two mkdir calls were missed, so "crossdir_rename" stats can be
wrong.

Test-Parameters: trivial mdscount=2 mdtcount=4 testlist=sanity env=ONLY=133a

Fixes: f0324c5c2f ("LU-14992 tests: sanity/replay-vbr mkdir on MDT0")
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I4e5c2e5504307462bff4012a13ef9deb24f8da8c
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49252
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>