WinRT: Exit process event loop if WaitForMoreEvents is not set

Change-Id: Ic74a75a56ba3f014b108e96d7a79a8623e6fa1d1
Reviewed-by: Andrew Knight <andrew.knight@digia.com>

src/corelib/kernel/qeventdispatcher_winrt.cpp

@@ -160,6 +160,8 @@ bool QEventDispatcherWinRT::processEvents(QEventLoop::ProcessEventsFlags flags)
             emit aboutToBlock();
             WaitForSingleObjectEx(GetCurrentThread(), 1, FALSE);
             emit awake();
+        } else {
+            break;
         }
     }
     d->interrupt = false;