Testcase for FSSA stabilized Stokes flow using an arrtificial glacier Case is based on the submitted paper by Löfgren, A., Zwinger, T., Råback, P., Helanow, C., and Ahlkrona, J.: Increasing numerical stability of mountain valley glacier simulations: implementation and testing of free-surface stabilization in Elmer/Ice, EGUsphere, https://doi.org/10.5194/egusphere-2023-1507, 2023.