snapshot/devmapper: log actual values to investigate #4965
snapshot/devmapper: log actual values to investigate #4965

This test has been flaky in GitHub Actions. This change logs the
values from devmapper to further investigate the issue.

Signed-off-by: Kazuyoshi Kato <732288c132d39c7d9231a005036e5ecd0fff1d64@amazon.com>

dmcgowan/containerd,containerd/containerd,estesp/containerd,vdemeester/containerd,estesp/containerd,mikebrow/containerd,containerd/containerd,thaJeztah/containerd,dmcgowan/containerd,mikebrow/containerd,vdemeester/containerd,thaJeztah/containerd