[corlib] Disable ThreadLocalTests.DisposeOnThreadExit on MonoTouch, it's randomly failing.

mcs/class/corlib/Test/System.Threading/ThreadLocalTests.cs

@@ -194,6 +194,9 @@ namespace MonoTests.System.Threading
 
 		[Test]
 		[Category ("NotWorking")] // Finalizers aren't guaranteed
+#if MONOTOUCH
+		[Category ("NotWorking")] // https://bugzilla.xamarin.com/show_bug.cgi?id=34617
+#endif
 		public void DisposeOnThreadExit ()
 		{
 			var threadLocal = new ThreadLocal<SetMreOnFinalize>();