Merge branch 'mac-dvc-setselections-performance' of https://github.com/vslavik/wxWidgets

Speed up wxDataViewCtrl::SetSelections() on macOS.

See https://github.com/wxWidgets/wxWidgets/pull/2084

interface/wx/dataview.h

@@ -1675,6 +1675,9 @@ public:
 
     /**
         Sets the selection to the array of wxDataViewItems.
+
+        Note that if @a sel contains any invalid items, they are simply
+        ignored.
     */
     virtual void SetSelections(const wxDataViewItemArray& sel);