PR: Improve "Jakob and Hanika (2019)" LUT unit tests. (#1050)
PR: Improve "Jakob and Hanika (2019)" LUT unit tests. (#1050)

* Fix caching in Jakob2019 module, for test speed

* remove unused imports

* change pytest cfg

Distribute tests to workers in groups for fixture cacheing

* Varnish "TestLUT3D_Jakob2019" class.

Co-authored-by: Tucker Downs <014a5f52613b4742a930f7f953ee9f59bdd19769@roevisual.us>
Co-authored-by: Tucker Downs <014a5f52613b4742a930f7f953ee9f59bdd19769@roevisual.com>
colour-science/colour