Fix fastscape test output

[anne-glerum]

With the changes described in #6963, the FastScape tests run to completion. This PR updates the test results. The main changes are:

• The number of mesh deformation DOFs increases by a factor ~4.
• The topography changes significantly (e.g. from 20 to 70 m), this could be related to the change in degrees of freedom.
• The test fastscape_test_silt_sand_parameters now does two more timesteps, but this corresponds to the set End time. When I introduced the test I had to increase the end time to get below sea level, I probably forgot to update the results accordingly 😔
• The test fastscape_kf_function_in_seconds now actually has output in seconds instead of years.
• The output folder names now include output- in the statistics file.
• Some changes in linear iterations for all solvers.

Concerning the first change, I don't think the recent changes to the mesh deformation functionality changed the order of the element for box geometries. The topography postprocessor outputs do not show more points either. I'll look into it.

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For new features/models or changes of existing features:

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[gassmoeller]

Looks good to me. But lets wait with merging this PR until we have resolved all of the test failures. Just in case we have to modify some of the tests again.