Don't eagerly set wxKeyEvent position fields.

This results in a noticeable delay when using wxGTK via a remote X11
connection for every key event as a round trip to server is needed to get the
mouse pointer position every time a key is pressed or released.

Only provide the position on demand. And explain that it's actually not very
useful as it's simply the same as the current mouse position.

Closes #14361.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72207 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/window.cpp

@@ -711,8 +711,6 @@ static void wxFillOtherKeyEventFields(wxKeyEvent& event,
     event.m_rawCode = (wxUint32) gdk_event->keyval;
     event.m_rawFlags = gdk_event->hardware_keycode;
 
-    wxGetMousePosition(&event.m_x, &event.m_y);
-    win->ScreenToClient(&event.m_x, &event.m_y);
     event.SetEventObject( win );
 }