LU-14514 tests: skip sanity-flr test_44b for interop

LU-14514 tests: skip sanity-flr test_44b for interop

Sanity-flr test_44b checks code that was only added in 2.14.56.

Test-Parameters: trivial serverversion=2.14.0 testlist=sanity-flr env=ONLY=44b
Fixes: 83c790cbf2f8 ("LU-14514 flr: mirror split should not make stale file")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I65cc59dbde3f9711b915a56730e221e224e9b715
Reviewed-on: https://review.whamcloud.com/46564
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>