[FR] global setup and teardown

**Is your feature request related to a problem? Please describe.**
I have benchmarks that need to create files. The benchmark is run multiple times to establish timing. But it's expensive and pointless to create and delete the files for each repetition.

**Describe the solution you'd like**
I expected setup to run once at the beginning and teardown to run once at the end. If that's not feasible then it would be good to have a real "global" setup/teardown that doesn't get run for each repetition.