Add caching to the jacobian definition method

This onleiner makes my richards example faster by 70%.

python/dune/codegen/sumfact/geometry.py

@@ -525,6 +525,7 @@ def name_meshwidth():
     return name
 
 
+@kernel_cached
 def _name_jacobian(i, j, restriction, visitor):
     """Return the (i, j) component of the jacobian of the geometry mapping
 
@@ -534,8 +535,6 @@ def _name_jacobian(i, j, restriction, visitor):
     Note: At the moment this only works for the mappings from reference cells
     to the cell and not for the geometry mappings of intersections.
     """
-    do_predicates = visitor.do_predicates
-
     # Create matrix sequence with derivative in j direction
     matrix_sequence = construct_basis_matrix_sequence(derivative=j,
                                                       facedir=get_facedir(restriction),