LU-17452 tests: fix interop sanityn tests with b2_15

LU-17452 tests: fix interop sanityn tests with b2_15

sanityn 77q and 77r require server fixes to pass.
The patch adds server version check in tests.

Fixes: 44cc782 ("LU-9859 ptlrpc: simplifying expression parsing in nrs_tbf")
Fixes: c098c09 ("LU-14976 nrs: change nrs policies at run time")
Test-Parameters: trivial
Test-Parameters: clientversion=2.15.4 testlist=sanityn
Test-Parameters: serverversion=2.15.4 testlist=sanityn
Signed-off-by: Etienne AUJAMES <eaujames@ddn.com>
Change-Id: I91b30284e9a3c24c9709215f509ca75923214c5b
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/53759
Tested-by: Maloo <maloo@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alex Deiter