user32: Add test for ComboBox repositioning behavior (try 2).

[Sergey Guralnik]

Marvin wrote 29.06.2012 10:14:
> 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
> http://testbot.winehq.org/JobDetails.pl?Key=19658
>
> Your paranoid android.
>
> === W7PRO (32 bit msg) ===
> msg.c:8219: Test failed: did not get zero count as expected (1).

This is unrelated to my patch.