user32: Add a test for ToUnicode - Win9x behaviour

[Andre Wisplinghoff]

Hello,

I think my patch [1] shouldn't be applied, because I didn't think about 
older versions of Windows. According to MSDN, ToUnicode has NT 3.1 as a 
minimum, meaning we should test if the function is unimplemented and 
skip the test in this case (Win9x Systems). Unfortunately I don't have a 
Win9x system ready for testing at the moment. Is adding the following 
after the first call to ToUnicode enough to handle this issue?

if (GetLastError() == ERROR_CALL_NOT_IMPLEMENTED)
{
    trace("Skipping the ToUnicode test on a Win9x platform\n");
    return;
}

Best Regards
-- Andre Wisplinghoff

[1] http://www.winehq.org/pipermail/wine-patches/2008-July/058745.html