Draft: Test that RPM installs/updates work without systemd
The mkdir -p /run/systemd/system /etc/systemd/system quietly enabled
systemd to be installed as a side effect if yum update -y && yum install -y yum-utils were called as part of the PackageCloud
installation script.
This masked the problem where a container without systemd would fail to install the runner.
This commit uses the same model as the Debian tests where the
service-specific tests run prepServiceInstallation is called explicitly
to set up systemd.
Relates to: