Revert "Merge branch 'bugfix/cmake-warns-about-missing-argument-in-add_python_test' into 'master'"

This reverts merge request !1121 (merged)

This fails with

/bin/sh: 1: cd: can't cd to /home/dedner/DUNE_PYTHON/dune-common/build-cmake/dune/python/test/CMAKE_GUARD

The CMAKE_GUARD argument is part of the dune_add_test command and not the cmake add_custom_targetso this has to be fixed differently. Don't understand why the pipelines worked but it fails for me locally and it is the wrong fix I think.