BXC13078 - Hard crash in icon rendering

The new Retina icon loader code was creating new pixbuf wrappers
when looking up the Retina icon variants, instead of using the
wrapper cache. This meant that the pixbuf could have multiple
togglerefs, which is invalid and would trigger an assert.

main/src/core/Mono.Texteditor/Mono.TextEditor/Gui/GtkWorkarounds.cs

@@ -1128,7 +1128,7 @@ public static Gdk.Pixbuf Get2xVariant (Gdk.Pixbuf px)
 			try {
 				IntPtr res = g_object_get_data (px.Handle, "gdk-pixbuf-2x-variant");
 				if (res != IntPtr.Zero && res != px.Handle)
-					return new Gdk.Pixbuf (res);
+					return (Gdk.Pixbuf) GLib.Object.GetObject (res);
 				else
 					return null;
 			} catch (DllNotFoundException) {