Make console a no-op for WinRT

Compared to other platforms there is no concept of a console
application in WinRT. Hence all applications need to be UI
applications and use winmain.
Furthermore winmain takes care of launch arguments to be
properly converted to arguments passed to user's main().

There is a chicken and egg problem with config.tests as
compilation needs to have an existing entry point which is not
available at configure time.
Hence hardcode the entry point to main for configuring to WinRT.
Those tests are pure compile tests, so the logic of the test
does not change.

Change-Id: I4d3186691a8440845c24b2529cc9646e86dfd8da
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>