[CI] Fix arg to check marks (#1064)

We used `-k "not benchmark"` which would filter out ANY test that
contained the word 'benchmark'.

This change fixes that by using the `-m` argument to only filter on
marks.

.github/workflows/run-tests.yml

@@ -66,4 +66,4 @@ jobs:
  - name: Run Tests
  run: |
  make -C tests/binaries -j ${{ env.GEF_CI_NB_CPU }}
- python${{ env.PY_VER }} -m pytest --forked -n ${{ env.GEF_CI_NB_CPU }} -v -k "not benchmark" tests/
+ python${{ env.PY_VER }} -m pytest --forked -n ${{ env.GEF_CI_NB_CPU }} -v -m "not benchmark" tests/