tests/docker: add coreutils to the package list

We need coreutils to run the IO tests so we need to include it in the
package list. Now we have the latest libvirt we can do that.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20251117115523.3993105-5-alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
24 files changed