LU-13390 tests: add debugging to sanity test_65n

LU-13390 tests: add debugging to sanity test_65n

Print out the layouts used in comparisons in case of error, so that
it is possible to debug intermittent test failures.

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: Ib81b10ff704998518275f737f028fb16391654ed
Reviewed-on: https://review.whamcloud.com/40600
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Olaf Faaland-LLNL <faaland1@llnl.gov>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>