[monotouch-test] Simplify NetworkReachabilityTest.CtorIPAddressPair test. (#7546)

* [monotouch-test] Improve reachability test.

Give up.

Different versions of OSes report different flags. Trying to
figure out which OS versions have which flags set turned out to
be a never-ending game of whack-a-mole, so just don't assert
that any specific flags are set.

tests/monotouch-test/SystemConfiguration/NetworkReachabilityTest.cs

@@ -100,14 +100,7 @@ namespace MonoTouchFixtures.SystemConfiguration {
 				NetworkReachabilityFlags flags;
 
 				Assert.IsTrue (nr.TryGetFlags (out flags), "#1");
-				// using Loopback iOS 10 / tvOS 10 returns no flags (0) on devices
-				// but only sometimes... so check for Reachable as well (as a flag).
-#if !MONOMAC
-				if ((Runtime.Arch == Arch.DEVICE) && TestRuntime.CheckXcodeVersion (8, 0))
-					Assert.That ((flags == (NetworkReachabilityFlags) 0) || ((flags & NetworkReachabilityFlags.Reachable) == NetworkReachabilityFlags.Reachable) , $"#1 Reachable: {flags.ToString ()}");
-				else
-#endif
-					Assert.That (flags, Is.EqualTo (NetworkReachabilityFlags.Reachable), "#1 Reachable");
+				CheckLoopbackFlags (flags, "1", true);
 			}
 
 			using (var nr = new NetworkReachability (null, address))
@@ -123,27 +116,22 @@ namespace MonoTouchFixtures.SystemConfiguration {
 				NetworkReachabilityFlags flags;
 
 				Assert.IsTrue (nr.TryGetFlags (out flags), "#3");
-				// using Loopback iOS 10 / tvOS 10 / macOS 10.12 returns no flags (0) on devices
-				var expected = (NetworkReachabilityFlags) 0;
-#if MONOMAC
-				if (!TestRuntime.CheckSystemVersion (PlatformName.MacOSX, 10, 12)) {
-					expected = NetworkReachabilityFlags.Reachable;
-					if (!TestRuntime.CheckSystemVersion (PlatformName.MacOSX, 10, 11))
-						expected |= NetworkReachabilityFlags.IsLocalAddress;
-				}
-#else
-				if ((Runtime.Arch == Arch.DEVICE) && TestRuntime.CheckXcodeVersion (8, 0)) {
-					// 
-				} else {
-					expected = NetworkReachabilityFlags.Reachable;
-					if (!TestRuntime.CheckXcodeVersion (7, 0))
-						expected |= NetworkReachabilityFlags.IsLocalAddress;
-				}
-#endif
-				Assert.That (flags, Is.EqualTo (expected), "#3 Reachable");
+				CheckLoopbackFlags (flags, "3", false);
 			}
 		}
 
+		void CheckLoopbackFlags (NetworkReachabilityFlags flags, string number, bool has_address)
+		{
+			var noFlags = (NetworkReachabilityFlags) 0;
+			var otherFlags = (flags & ~(NetworkReachabilityFlags.Reachable | NetworkReachabilityFlags.IsLocalAddress | NetworkReachabilityFlags.IsDirect));
+
+			// Different versions of OSes report different flags. Trying to
+			// figure out which OS versions have which flags set turned out to
+			// be a never-ending game of whack-a-mole, so just don't assert
+			// that any specific flags are set.
+			Assert.AreEqual (noFlags, otherFlags, $"#{number} No other flags: {flags.ToString ()}");
+		}
+
 		[Test]
 		public void Ctor_Invalid ()
 		{