Bump maccore for fixing #3 of bug #41083

   [Xamarin.Hosting] Set a default simulator if nothing is provided to mlaunch. Fix #41083 part 3

    The string to represent a specific simulator is not something you can
    easily remember but it's often not very important.

    This will start the most basic simulator, by default, instead of throwing
    an NRE that does not mention a (now un-) required parameter is missing.

    > Failed to launch the simulator: Object reference not set to an instance of an object
    > error MT1008: Failed to launch the simulator: Object reference not set to an instance of an object

    https://bugzilla.xamarin.com/show_bug.cgi?id=41083

mk/xamarin.mk

@@ -1,5 +1,5 @@
 ifdef ENABLE_XAMARIN
-NEEDED_MACCORE_VERSION := 16ebbc5b4401ecdd86c60bb0ddbf3234334f63b5
+NEEDED_MACCORE_VERSION := 53cb35859d3a645290a6cd879df574c52c3ba7f2
 NEEDED_MACCORE_BRANCH := master
 
 MACCORE_DIRECTORY := maccore