[monotouch-test] Fix ContactStoreTest for watchOS (#3006)

Backport/merge of PR #306 to avoid random failures on bots.
Should fix https://github.com/xamarin/maccore/issues/577

tests/monotouch-test/Contacts/ContactStoreTest.cs

@@ -50,7 +50,7 @@ namespace MonoTouchFixtures.Contacts {
 				var contacts = store.GetUnifiedContacts (predicate, fetchKeys, out error);
 				// we can't be sure what's on devices, so check there's no error is the only thing we do
 				// but it's in the default simulator build (but not the watchOS simulator)
-#if !MONOMAC
+#if !MONOMAC && !__WATCHOS__
 				if ((error == null) && (Runtime.Arch == Arch.SIMULATOR)) {
 					Assert.That (contacts.Length, Is.EqualTo (1), "Length");
 					identifier = contacts [0].Identifier;