[ADVAPI32] "Minimally" improve the SaferComputeTokenFromLevel() stub. (#5435) CORE-14015, CORE-6942

This makes Windows 2003 CMD.EXE to start batch files again.
Addendum to commit 17d42ae2a (r58868).

Replaces PR #3084 by freely importing and adapting Wine patch
https://github.com/wine-mirror/wine/commit/17110a0a890d2bacb5b348bd9bb3cef10d144e19
```
advapi32: Improve the SaferComputeTokenFromLevel stub.
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47274
Signed-off-by: Hans Leidekker <[e-mail]>
Signed-off-by: Alexandre Julliard <[e-mail]>
```

dll/win32/advapi32/sec/safer.c

···
     _Inout_opt_ PVOID pReserved)
 {
     FIXME("(%p, %p, %p, 0x%lx, %p) stub\n", LevelHandle, InAccessToken, OutAccessToken, dwFlags, pReserved);
-    SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
-    return FALSE;
+    *OutAccessToken = (dwFlags & SAFER_TOKEN_NULL_IF_EQUAL) ? NULL : UlongToHandle(0xdeadf00d);
+    return TRUE;
 }