user32/tests: Add tests for MsgWaitForMultipleObjectsEx.

[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=10062

Your paranoid android.


=== w7u (32 bit msg) ===
msg.c:12147: Test failed: unexpected hwnd 0014013C
msg.c:12169: Test failed: bad time 308c6/308d6