Fix user data pointer setting on x86_64 platform on windows

Using 0 as index offset to set user data in window handle,
is failing on x64 platform with:

ERROR_INVALID_INDEX 1413 (0x585)

To find it out GetLastError() can be used:

SetLastError(0);
LONG_PTR salFrameBack = SetWindowLongPtrW(hWnd, 0, (LONG_PTR)pFrame);
DWORD status = GetLastError();

Switching to documented GWLP_USERDATA instead, solved the problem.

Change-Id: I496ed2915e44309eaaaa4b576dca30b0051bdbfd
Reviewed-on: https://gerrit.libreoffice.org/13807Reviewed-by: David Ostrovsky <david@ostrovsky.org>
Tested-by: David Ostrovsky <david@ostrovsky.org>

vcl/inc/win/saldata.hxx

@@ -200,12 +200,12 @@ OUString ImplSalGetUniString(const sal_Char* pStr, sal_Int32 nLen = -1);
 int ImplSalWICompareAscii( const wchar_t* pStr1, const char* pStr2 );
 
 #define SAL_FRAME_WNDEXTRA          sizeof( DWORD )
-#define SAL_FRAME_THIS              0
+#define SAL_FRAME_THIS              GWLP_USERDATA
 #define SAL_FRAME_CLASSNAMEW        L"SALFRAME"
 #define SAL_SUBFRAME_CLASSNAMEW     L"SALSUBFRAME"
 #define SAL_TMPSUBFRAME_CLASSNAMEW  L"SALTMPSUBFRAME"
 #define SAL_OBJECT_WNDEXTRA         sizeof( DWORD )
-#define SAL_OBJECT_THIS             0
+#define SAL_OBJECT_THIS             GWLP_USERDATA
 #define SAL_OBJECT_CLASSNAMEA       "SALOBJECT"
 #define SAL_OBJECT_CHILDCLASSNAMEA  "SALOBJECTCHILD"
 #define SAL_COM_CLASSNAMEW          L"SALCOMWND"