[xharness] Fix mlaunch lookup.

tests/xharness/Harness.cs

@@ -77,9 +77,15 @@ namespace xharness
 
 		public string MlaunchPath {
 			get {
-				var path = Path.GetFullPath (Path.Combine (Path.GetDirectoryName (RootDirectory), "tools", "mlaunch", "mlaunch"));
+				var path = Path.GetFullPath (Path.Combine (Path.GetDirectoryName (Path.GetDirectoryName (RootDirectory)), "maccore", "tools", "mlaunch", "mlaunch"));
+				if (!File.Exists (path)) {
+					Log ("Could not find mlaunch locally ({0}), will try in Xamarin Studio.app.", path);
+					path = "/Applications/Xamarin Studio.app/Contents/Resources/lib/monodevelop/AddIns/MonoDevelop.IPhone/mlaunch.app/Contents/MacOS/mlaunch";
+				}
+
 				if (!File.Exists (path))
 					throw new FileNotFoundException (string.Format ("Could not find mlaunch: {0}", path));
+				
 				return path;
 			}
 		}