LU-14492 tests: sanity 27Cb skip condition

LU-14492 tests: sanity 27Cb skip condition

The test skip condition is wrong and causes the
test to be skipped if large xattrs are not supported.
Fixing other tests as well.

Test-Parameters: trivial
Fixes: 591a9b4ce ("LU-9846 lod: Add overstriping support")
HPE-bug-id: LUS-9454
Signed-off-by: Alexander Zarochentsev <alexander.zarochentsev@hpe.com>
Change-Id: I7b9d96abb5e4cf2a3955e20828e57a64978e6229
Reviewed-on: https://review.whamcloud.com/41903
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Elena Gryaznova <c17455@cray.com>