Stop duplicating wxFrame dtor in all ports.

wxGTK1, wxGTK, wxMSW and wxOSX all did the same thing in their wxFrame dtor,
so just do it in wxFrameBase instead.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76804 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/frame.h

@@ -39,8 +39,6 @@ public:
                 long style = wxDEFAULT_FRAME_STYLE,
                 const wxString& name = wxFrameNameStr);
 
-    virtual ~wxFrame();
-
 #if wxUSE_STATUSBAR
     void SetStatusBar(wxStatusBar *statbar) wxOVERRIDE;
 #endif // wxUSE_STATUSBAR