Testing upscale_perm: Change to periodic BCs for test on PeriodicTilted.grdecl
Add grid models to be used for testing upscale_perm
Add new reference solutions for testing upscale_perm
Add more tests for upscale_perm

Also write a macro for testing upscale_perm on different models.
This change makes it easier to add more tests and to keep the code tidy.