pkg/bpf: Add test for map.DeleteAll()
pkg/bpf: Add test for map.DeleteAll()

Add a test that ensures that when deleting all elements in the map, all
elements are deleted.

Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@cilium.io>

michi-covalent/cilium,cilium/cilium,tklauser/cilium,tgraf/cilium,michi-covalent/cilium,cilium-team/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,tklauser/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,tgraf/cilium,cilium-team/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,michi-covalent/cilium