user32: Allow a NULL foreground window in the tests

[Dmitry Timoshkov]

"James Hawkins" <truiken at gmail.com> wrote:

>> NULL foreground window is already allowed, you just need to fix the callers
>> of check_wnd_state() to pass 0 for foreground.
>>
> 
> It's not consistent across platforms.

Passing 0 for foreground will make the same thing as your patch - prevent
failures when there is no consistent foreground window, i.e. when the test
is useless.

-- 
Dmitry.