mshtml/tests: Use todo_wine_if() in tests

[Marvin]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
https://testbot.winehq.org/JobDetails.pl?Key=20627

Your paranoid android.


=== wvistau64 (32 bit htmldoc) ===
htmldoc.c:5329: Test failed: elem == NULL