[PATCH] comctl32/tests: Fix a couple of uninitialized variables (Coverity)

[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=6070

Your paranoid android.


=== wvistau64 (32 bit button) ===
button.c:654: Test failed: BM_SETCHECK on a button: the msg sequence is not complete: expected 0000 - actual 000f