Remove compile-time checks for always defined WM_XXX in wxMSW

The symbols in question are present at least since XP, and most of them since
Windows 2000, so remove preprocessor checks for them, they shouldn't be needed
when any remotely current compiler/SDK.

src/msw/window.cpp

@@ -71,9 +71,6 @@
     #include "wx/access.h"
     #include <ole2.h>
     #include <oleacc.h>
-    #ifndef WM_GETOBJECT
-        #define WM_GETOBJECT 0x003D
-    #endif
     #ifndef OBJID_CLIENT
         #define OBJID_CLIENT 0xFFFFFFFC
     #endif
@@ -3292,7 +3289,6 @@ wxWindowMSW::MSWHandleMessage(WXLRESULT *result,
             }
 #endif
 
-#if defined(WM_HELP)
         case WM_HELP:
             {
                 // by default, WM_HELP is propagated by DefWindowProc() upwards
@@ -3328,7 +3324,6 @@ wxWindowMSW::MSWHandleMessage(WXLRESULT *result,
                 }
             }
             break;
-#endif // WM_HELP
 
         case WM_CONTEXTMENU:
             {