CI: make sure EXTERNALLY-MANAGED is absent on Arch Linux (#7172)
Make sure EXTERNALLY-MANAGED is absent on Arch.
(cherry picked from commit f3a02b3efb)
Co-authored-by: Felix Fontein <felix@fontein.de>
* Make sure that every test that uses package: requires setup_pkg_mgr.
* Upgrade system packages for Arch Linux.
* Re-enable java keytool tests on Arch.