Fix issue where loopback interface causes exception 1027045

[mderoy]

Inital WIP commit. Still needs more changes, testing, etc.
we should probably upstream this once we're done.

manually tested output of this against .netFW

(Scripting Upgrade) Fixed an issue where GetIPv4Properties could throw an exception when called on the loopback network interface (case 1027045)

public void Test()
{
	var interfaces = NetworkInterface.GetAllNetworkInterfaces();
	foreach (NetworkInterface ni in interfaces)
	{
		var ipv4Properties = ni.GetIPProperties().GetIPv4Properties();
		UnityEngine.Debug.Log(ni.Name + " " + ipv4Properties.Index);
		var isDHCP = ipv4Properties.IsDhcpEnabled;
		UnityEngine.Debug.Log("isDHCP " + isDHCP);
		var iswins = ipv4Properties.UsesWins;
		UnityEngine.Debug.Log("UsesWins " + iswins);



		var dhcpserveraddrcol = ni.GetIPProperties().DhcpServerAddresses;
		foreach (var dhcp in dhcpserveraddrcol)
			UnityEngine.Debug.Log("dhcpserver " + dhcp.Address);
		var gatewayipaddressinformationcol = ni.GetIPProperties().GatewayAddresses;
		foreach (var gateway in gatewayipaddressinformationcol)
			UnityEngine.Debug.Log("gatewayserver " + gateway.Address);
		var unicastipaddresinformationcol = ni.GetIPProperties().UnicastAddresses;
		foreach (var unicast in unicastipaddresinformationcol)
			UnityEngine.Debug.Log("unicastserver " + unicast.Address);
		var winsipaddresscol = ni.GetIPProperties().WinsServersAddresses;
		foreach (var ftw in winsipaddresscol)
			UnityEngine.Debug.Log("winsserver " + ftw.Address);
	}
}

[mderoy]

They've accepted these changes upstream. I'll merge now. should be same changes as upstream (except where upstream moved a few things around)