user32: Return early on child windows in DrawMenuBar

[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=9017

Your paranoid android.


=== w7u (32 bit msg) ===
msg.c:12111: Test failed: unexpected hwnd 0014013C
msg.c:12133: Test failed: bad time 308e5/308f5