DNS lookups fail in qemu-user when it is built on Alpine: https://bugs.alpinelinux.org/issues/8131
Until this is resolved, we fetch the binaries from Debian and use those instead. The final stage
of the Dockerfile is still based on scratch.
We can revert this once the Alpine issue is fixed.
Signed-off-by: Justin Barrick <jbarrick@cloudflare.com>