remove unneeded wxCHECK_MSG: GetNextMessage() can get the msg even if the event loop...

remove unneeded wxCHECK_MSG: GetNextMessage() can get the msg even if the event loop is not running; the check breaks the:
  while ( loop->Pending() )
    loop->Dispatch();
snippet in console apps since wxConsoleEventLoop::Dispatch calls GetNextMessage() (see also the TimerEventTestCase cppunit).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@59636 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775