[tests][monotouch] Remove the ignore on MPVolumeView added in xcode9 beta 3 - it seems to work fine now (#3284)

tests/introspection/iOS/iOSApiCtorInitTest.cs

@@ -210,8 +210,6 @@ namespace Introspection {
 				return true;
 			case "INBookRestaurantReservationIntentResponse": // iOS 11 beta 2: stack overflow in description. radar:32945914
 				return true;
-			case "MPVolumeView": // Started failing with Xcode 9 beta 3
-				return true;
 			case "IOSurface": // Only works on device
 			case "NEHotspotEapSettings": // Wireless Accessory Configuration is not supported in the simulator.
 			case "NEHotspotConfigurationManager":

tests/monotouch-test/MediaPlayer/VolumeViewTest.cs

@@ -29,9 +29,6 @@ namespace MonoTouchFixtures.MediaPlayer {
 	[Preserve (AllMembers = true)]
 	public class VolumeViewTest {
 
-		// TODO: Test temporarily ignored.
-		// Reason: MPVolumeView started failing with iOS 11 beta 3.
-		[Ignore]
 		[Test]
 		public void InitWithFrame ()
 		{