Fail slow tests

[user27182]

Overview

Use https://github.com/jwodder/pytest-fail-slow to fail slow tests

[user27182]

This plugin is very helpful. Already found some low-hanging fruit to speed up CI:

tiny pages tests are taking a long time on macOS:

___________________ test_tinypages[False-PYVISTA_PLOT_SKIP] ____________________
Test passed but took too long to run: Duration 46.58355129099982s > 1.0s
_______________ test_tinypages[False-PYVISTA_PLOT_SKIP_OPTIONAL] _______________
Test passed but took too long to run: Duration 46.18138849999991s > 1.0s
____________________ test_tinypages[True-PYVISTA_PLOT_SKIP] ____________________
Test passed but took too long to run: Duration 46.061539541s > 1.0s
_______________ test_tinypages[True-PYVISTA_PLOT_SKIP_OPTIONAL] ________________
Test passed but took too long to run: Duration 46.224338708000005s > 1.0s

plus others

______________________ test_volume_rendering_rectilinear _______________________
Test passed but took too long to run: Duration 43.41575133300012s > 1.0s
___________________________________ test_pbr ___________________________________
Test passed but took too long to run: Duration 142.26619474999984s > 1.0s