LU-17196 tests: sanity-lnet test_310 MR support

LU-17196 tests: sanity-lnet test_310 MR support

Modify sanity-lnet test_310 to work with multi-rail configs.

Test-Parameters: trivial testlist=sanity-lnet env=ONLY=310
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: I19d02d5a7da1f9ca2b9c0de791bb63b94dff1fdd
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/52695
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Cyril Bordage <cbordage@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>