sys: add missing pre-condition checks in tests
sys: add missing pre-condition checks in tests

SetOOMScore requires both privileged (root) and non-user namespace,
for negative values, so adjust the pre-conditions accordingly.

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

containerd/containerd,mikebrow/containerd,thaJeztah/containerd,vdemeester/containerd,estesp/containerd,dmcgowan/containerd,estesp/containerd,mikebrow/containerd,vdemeester/containerd,thaJeztah/containerd,containerd/containerd,dmcgowan/containerd