Update icu4c and xz utils versions so they don't fetch from sourceforge
Their maintainers only host supported versions on their website, and archived versions redirect to sourceforge
Fixes https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1129
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Their maintainers only host supported versions on their website, and archived versions redirect to sourceforge
Fixes https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1129