LU-11170 tests: don't fail sanity/415 in VM

LU-11170 tests: don't fail sanity/415 in VM

Don't fail sanity test_415 when running in a VM due to variable
runtimes for the tests.

A proper solution would be to examine the logs to determine if
the renames are blocked or just all slow due to VM contention.

Lustre-change: https://review.whamcloud.com/50654
Lustre-commit: 73a7b1c2a3f0114618db7781adb56974ed682f24

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I1a5d0f601705c9ec8559e760c4ec27c7f83ebbe5
Reviewed-by: Alex Deiter <alex.deiter@gmail.com>
Reviewed-by: Vikentsi Lapa <vlapa@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/50938
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>