Test on pyramid intermittently failing

[mscroggs]

A unit test on a pyramid seems to be intermittently failing.

It failed here before I reran: https://github.com/FEniCS/basix/pull/267/checks?check_run_id=3564790994

It was showing lots of nans; I think it was using GLL points; might be due to an error in their creation. (I hit "rerun tests" to see if it happens every time before realising this meant I lost the failure message.)

This appears to be another example: https://github.com/FEniCS/basix/runs/3494137696?check_suite_focus=true

[mscroggs]

This looks like another one: https://github.com/FEniCS/basix/runs/3494015368?check_suite_focus=true

[mscroggs]

Another one? https://github.com/FEniCS/basix/runs/3494014069?check_suite_focus=true

[mscroggs]

In d5ec760, I've changed the problematic test to use equispaced points in case the issue is with GLL points on a pyramid

[mscroggs]

https://github.com/FEniCS/basix/pull/270/checks?check_run_id=3565262514