LU-15913 tests: add rename stress test via racer

LU-15913 tests: add rename stress test via racer

Add a rename stress test using the racer framework.  Use
mrename if found, to avoid stat and allow directory rename.
Sometimes create and rename files to/from subdirectories.

Run e2fsck after every run to confirm filesystem structure.

Allow tunable parameters via environment variables so they
can be set via Test-Parameters.  Parameters can be set on
different nodes via variables CLIENT_LCTL_SETPARAM_PARAM,
MDS_LCTL_SETPARAM_PARAM, OSS_LCTL_SETPARAM_PARAM.

Lustre-change: https://review.whamcloud.com/47643
Lustre-commit: TBD (from 6c63c882741637a246012a81e41289fcf0e2dbbe)

Test-Parameters: trivial testlist=racer env=ONLY=2
Test-Parameters: testlist=racer env=ONLY=2 mdtcount=2
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I2ae034b864a5ccb8a59bf7028d22cd67c643f51f
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/53751
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>