reject_list filters are sometimes missed

At the moment of writing we have the following in the reject_list:

# test suite fails to start properly (disk space in unstable)
nvidia-cuda-toolkit stable arm64
# test suite fails to start properly (disk space in unstable)
nvidia-cuda-toolkit * ppc64el

which was updated from

# test suite fails to start properly
nvidia-cuda-toolkit stable arm64
# test suite fails to start properly
nvidia-cuda-toolkit stable ppc64el

While tests remained blocked on arm64/stable, tests started to be accepted on ppc64el/stable.

PS: I'll also block arm64/* soon, so the issue will look different again.