bcachefs: Fix unit & perf tests for snapshots

This finishes updating the unit & perf tests for snapshots - btrees that
use snapshots now always require the snapshot field of the start
position to be a valid snapshot ID.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This commit is contained in:
Kent Overstreet 2021-12-15 20:38:56 -05:00 • committed by Kent Overstreet
commit 6f83cb84bb