Pass arguments to `ctest`?

[joewallwork]

Whilst working on #239, I figured out how to pass unused arguments to ctest. (See 249_ctest-args.) This could be useful for, e.g., running specific tests from the run_test_suite script.

However, my version of ctest (from CMake 3.22.1) silently drops invalid arguments, which I don't think we want (see https://gitlab.kitware.com/cmake/cmake/-/issues/24227). This was fixed for a later version of CMake (see https://gitlab.kitware.com/cmake/cmake/-/merge_requests/9383), though.