WinRT: Fix various test compilations

- Remove irrelevant test subdirs via .pro files
- Follow WinCE codepaths where applicable
- Replace unsupported Win32 APIs with WinRT equivalents

This does not aim to fix any failures in the tests themselves; it only
makes them compile.

Change-Id: Ia82bc0cc402891f8f6238d4c261ee9152b51be80
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>