tests/functional: add a generalized uncompress helper

There are many types of compression that the tests deal with, and
it makes sense to have a single helper 'uncompress' that can deal
with all.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20241217155953.3950506-25-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2 files changed