Only consider perforation in the interior of the local grid.

This is needed for distributed wells to save most of the code
from checking whether a perforation is in the interior.

We add new methods compressedIndexForInterior that return -1
for non-interior cells and use that for the wells. This restores
the old behaviour before 1cfe3e0aad

opm/simulators/wells/BlackoilWellModelGeneric.hpp

@@ -374,7 +374,8 @@ protected:
     void runWellPIScaling(const int timeStepIdx,
                           DeferredLogger& local_deferredLogger);
 
-    virtual int compressedIndex(int cartesian_cell_idx) const = 0;
+    /// \brief get compressed index for interior cells (-1, otherwise
+    virtual int compressedIndexForInterior(int cartesian_cell_idx) const = 0;
 
 
     Schedule& schedule_;