Bug#1088865: dolfin: autopkgtests fail

[Drew Parsons]

Source: dolfin
Followup-For: Bug #1088865

I tested my own legacy code with dolfin on python3.13.
It's still running perfectly fine.

It looks like the damage here is restricted to the mesh iterators,
in MESHITERATOR_MACRO and also mesh.SubsetIterator()

If you're not using those iterators, then the code is still okay.
We can therefore downgrade the bug severity if we skip the 3 failing tests.
The failure looks bad but is not completely blocking use of the package.