Mark wxTextCtrl dirty before handling event in wxOSX

This fixes behaviour of wxSpinCtrl which otherwise could still use the
old value of its text part when processing spin buttons press.

Closes https://github.com/wxWidgets/wxWidgets/pull/2092

src/osx/cocoa/window.mm

@@ -2443,7 +2443,10 @@ void wxWidgetCocoaImpl::controlTextDidChange()
         wxTextCtrl *tc = wxDynamicCast( wxpeer , wxTextCtrl );
         wxComboBox *cb = wxDynamicCast( wxpeer , wxComboBox );
         if ( tc )
+        {
+            tc->MarkDirty();
             tc->SendTextUpdatedEventIfAllowed();
+        }
         else if ( cb )
             cb->SendTextUpdatedEventIfAllowed();
         else