Add a mixed+hs-v23-ipv6 network to tor's test-network
We want to add the new mixed+hs-v23-ipv6 chutney network from #33333 (moved) to tor's makefile tests:
- test-network-all
- test-network-ipv6
We'll need some minor refactoring, so that we can test for "ipv6" and "mixed", before using this network.
I think the resulting code will be simpler.
We can pass the following network lists to the test-network-run target:
- unconditional (ipv4 and not mixed)
- ipv6
- mixed
- mixed_ipv6
Then we can:
- test for ipv6 and mixed in separate tests,
- set flags for mixed and ipv6, and
- skip or use the right network lists.