TestFloor: consistent timeouts on `el8`
After !10405 (merged), VTK::RenderingOpenGL2Cxx-TestFloor
consistently times out (100s). It's not clear how the changes would have affected this test.
After !10405 (merged), VTK::RenderingOpenGL2Cxx-TestFloor
consistently times out (100s). It's not clear how the changes would have affected this test.