Allow using compressions unsupported by containerd on non-overlayfs snapshotter
Allow using compressions unsupported by containerd on non-overlayfs snapshotter

Signed-off-by: Kohei Tokunaga <72a466a7d91579e23b8af87d6766ee221241ce87@gmail.com>

tonistiigi/buildkit_poc,tonistiigi/buildkit_poc