restore fixed interpolation test

8 jobs for oldsympy in 17 minutes and 51 seconds (queued for 2 seconds)
Name Stage Failure
failed
pycodegen-integration Test
$ git submodule foreach git fetch origin
Entering 'lbmpy'
warning: redirecting to https://i10git.cs.fau.de/pycodegen/lbmpy.git/
Entering 'lbmpy_walberla'
warning: redirecting to https://i10git.cs.fau.de/pycodegen/lbmpy_walberla.git/
Entering 'pygrandchem'
fatal: unable to access 'https://gitlab-ci-token:[MASKED]@i10git.cs.fau.de/pycodegen/pygrandchem/': Failed to connect to i10git.cs.fau.de port 443: Connection refused
Stopping at 'pygrandchem'; script returned non-zero status.
ERROR: Job failed: exit code 1