prober: Consolidate IP selection for probing
prober: Consolidate IP selection for probing

Previously, the ICMP and HTTP probers could be inconsistent in the set
of hosts that they selected to ping, because the ICMP ping would skip
garbage IPs (because they had to be resolved first), whereas the HTTP
prober would attempt to ping them. Consolidate the validation of the
IPs so that these paths are consistent.

Signed-off-by: Joe Stringer <da02367898403910c66f5d62c3a247888772ce8a@gmail.com>

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