[Bug 36185] New: comctl32/button tests shows an unitialized variable under valgrind

https://bugs.winehq.org/show_bug.cgi?id=36185

Bug ID: 36185
           Summary: comctl32/button tests shows an unitialized variable
                    under valgrind
           Product: Wine
           Version: 1.3.13
          Hardware: x86
                OS: Linux
            Status: NEW
          Keywords: download, source, testcase
          Severity: minor
          Priority: P2
         Component: comctl32
          Assignee: [e-mail]
          Reporter: [e-mail]
                CC: [e-mail]

==2251== Conditional jump or move depends on uninitialised value(s)
==2251==    at 0x4F10DEC: winetest_vok (test.h:311)
==2251==    by 0x4F10FFA: winetest_ok (test.h:357)
==2251==    by 0x4E65D82: test_button_class (button.c:748)
==2251==    by 0x4E6628D: func_button (button.c:810)
==2251==    by 0x4F119B1: run_test (test.h:584)
==2251==    by 0x4F11DA0: main (test.h:654)
==2251==  Uninitialised value was created by a stack allocation
==2251==    at 0x4E65A95: test_button_class (button.c:722)
==2251== 
{
   <insert_a_suppression_name_here>
   Memcheck:Cond
   fun:winetest_vok
   fun:winetest_ok
   fun:test_button_class
   fun:func_button
   fun:run_test
   fun:main
}

looking at the code, it's semi-expected, as it's a todo_wine:
    ret = GetClassInfoExW(NULL, nameW, &ex2W);
todo_wine {
    ok(ret, "got %d\n", ret);
    ok(ex2W.lpfnWndProc == exW.lpfnWndProc, "got %p, %p\n", exW.lpfnWndProc,
ex2W.lpfnWndProc);
}