[tests] Adjust ConfigTest to cope with different behavior when using NativeAOT.

tests/monotouch-test/mono/ConfigTest.cs

@@ -13,8 +13,17 @@ namespace MonoTouchFixtures {
 		[Test]
 		public void Existence ()
 		{
+#if NATIVEAOT
+#if __MACCATALYST__ || __MACOS__
+			var config_dir = Path.Combine (Path.GetDirectoryName (AppContext.BaseDirectory.TrimEnd ('/')), "MonoBundle");
+#else
+			var config_dir = AppContext.BaseDirectory;
+#endif
+			var config_file = Path.Combine (config_dir, Assembly.GetExecutingAssembly ().GetName ().Name + ".dll.config");
+#else
 			var config_file = Assembly.GetExecutingAssembly ().Location + ".config";
-			Assert.True (File.Exists (config_file), "existence");
+#endif
+			Assert.That (config_file, Does.Exist, "existence");
 			Assert.That (File.ReadAllText (config_file), Contains.Substring ("<secretMessage>Xamarin rocks</secretMessage>"), "content");
 		}
 	}