enable CI

foamgrid-test.cc and local-refine-test.cc are expected to fail with

```
Dune::GridError [checkIntersectionIterator:[...]/dune/grid/test/checkintersectionit.hh:600]:
Integral over outer normals on affine entity is nonzero: -1 0 0
```

The test from dune-grid doesn't quite apply to FoamGrid and needs to
be adapted to make the tests pass.