Fix saving/restoring window position for maximized windows

Save both the normal window geometry and its maximized position instead
of saving just its current position. This fixes restoring geometry of
the maximized windows as previously they were always restored on the
primary monitor, as their original position was lost.

Use the native {Get,Set}WindowPlacement() functions for a MSW-specific
wxTLWGeometry implementation to achieve this.

Closes #16335.

include/wx/private/tlwgeom.h

@@ -57,6 +57,9 @@ public:
 #define wxPERSIST_TLW_MAXIMIZED "Maximized"
 #define wxPERSIST_TLW_ICONIZED "Iconized"
 
+// MSW has its own native implementation and doesn't use this class.
+#ifndef __WXMSW__
+
 class wxTLWGeometryGeneric : public wxTLWGeometryBase
 {
 public:
@@ -166,8 +169,12 @@ private:
     bool m_maximized;
 };
 
+#endif // !__WXMSW__
+
 #ifdef __WXGTK20__
     #include "wx/gtk/private/tlwgeom.h"
+#elif defined(__WXMSW__)
+    #include "wx/msw/private/tlwgeom.h"
 #else
     class wxTLWGeometry : public wxTLWGeometryGeneric
     {