packagegroup-fsl-tools-testapps: Install more Wayland-related utilities

In case Wayland is in use include:

 - weston
 - weston-examples
 - gtk+3-demo
 - clutter-1.0-examples (if not in i.MX6SL)

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
fsl-image-machine-test: Rework image to reduce duplication

As packagegroup-fsl-tools-testapps now include the Wayland specific
testing utilities we can remove them from the explicit installation
inside the image.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>