ieframe/tests: Skip some tests on Windows if WebBrowser is not supported.

[Francois Gouget]

The errors that TestBot reports on W2KPROSP4 
(http://testbot.winehq.org/JobDetails.pl?Key=14328) are totally 
unrelated to this patch or to the next one ('Don't crash if 
IWebBrowser2_get_LocationURL() fails.').


-- 
Francois Gouget <fgouget at free.fr>              http://fgouget.free.fr/
            Before you criticize someone, walk a mile in his shoes.
       That way, if he gets angry, he'll be a mile away - and barefoot.