Reduce runtime of quest interesection tests

[kennyweiss]

The quest_intersection_shaper unit tests are taking too long to run for Debug CPU configurations.

In #1127, @kennyweiss explicitly set the `NUM_OMP_THREADS for the test to 8 since using all threads on the system (the previous implicit default) was causing occasional hangs.

One idea to reduce the runtime might be to lower the default number of octahedral refinements from 7 to something like 5. We expect this to lower the volume fraction accuracy, so we'd need to also update the baselines in axom_data.