Speed up Aggregator Unit tests (also PyAutoLens / CTI)

[Jammy2211]

The following unit tests run very slow:

https://github.com/Jammy2211/PyAutoGalaxy/tree/feature/autofit_outputs/test_autogalaxy/aggregator
https://github.com/Jammy2211/PyAutoLens/tree/feature/autofit_outputs/test_autolens/aggregator
https://github.com/Jammy2211/PyAutoCTI/tree/feature/autofit_outputs/test_autocti/aggregator

Is there a trick we can use to speed them up?