[PATCH] comctl32/tests: Replace some asserts with regular test calls

[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=36084

Your paranoid android.


=== wvistau64 (32 bit listbox) ===
listbox.c:905: Test failed: SendMessage(LB_DIR, DDL_DIRECTORY|DDL_EXCLUSIVE, *) failed err 18

=== wvistau64 (64 bit listbox) ===
listbox.c:905: Test failed: SendMessage(LB_DIR, DDL_DIRECTORY|DDL_EXCLUSIVE, *) failed err 18