Changed GetNetworkInterfaces method to to retrieve information relate…

…d to all interfaces (dotnet#100824)

* Add IncludeAllInterfaces as falg to reterive all avaliable interfaces including disabled ones

* Update tests to accommodate new adapters. Ensure adapters reflect proper speeds; non-positive speeds indicates absence of physical address.

* Removed unnecessary assertion

* Add assertion over physical address bytes

src/libraries/System.Net.NetworkInformation/src/System/Net/NetworkInformation/SystemNetworkInterface.cs

@@ -85,8 +85,7 @@ internal static unsafe NetworkInterface[] GetNetworkInterfaces()
             List<SystemNetworkInterface> interfaceList = new List<SystemNetworkInterface>();
 
             Interop.IpHlpApi.GetAdaptersAddressesFlags flags =
-                Interop.IpHlpApi.GetAdaptersAddressesFlags.IncludeGateways
-                | Interop.IpHlpApi.GetAdaptersAddressesFlags.IncludeWins;
+                Interop.IpHlpApi.GetAdaptersAddressesFlags.IncludeAllInterfaces;
 
             // Figure out the right buffer size for the adapter information.
             uint result = Interop.IpHlpApi.GetAdaptersAddresses(

src/libraries/System.Net.NetworkInformation/tests/FunctionalTests/NetworkInterfaceBasicTest.cs

@@ -22,6 +22,7 @@ public NetworkInterfaceBasicTest(ITestOutputHelper output)
         [Fact]
         public void BasicTest_GetNetworkInterfaces_AtLeastOne()
         {
+
             Assert.NotEqual<int>(0, NetworkInterface.GetAllNetworkInterfaces().Length);
         }
 
@@ -50,7 +51,8 @@ public void BasicTest_AccessInstanceProperties_NoExceptions()
 
                 if (nic.NetworkInterfaceType == NetworkInterfaceType.Ethernet)
                 {
-                    Assert.Equal(6, nic.GetPhysicalAddress().GetAddressBytes().Length);
+                    var physicalAddressLength = nic.GetPhysicalAddress().GetAddressBytes().Length;
+                    Assert.True(physicalAddressLength == 0 || physicalAddressLength == 6);
                 }
             }
         }