CConnman::AddConnection locks m_nodes_mutex and counts existing connections of the requested type even for types that have no limit (ADDR_FETCH and FEELER), then discards the count. Move the count inside the max_connections != std::nullopt check so we only take the lock and walk the node list when there is a limit to enforce.
No behavior change: when max_connections is std::nullopt the old code computed a count it never used.
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For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35825.
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This hasn't received any review for some time now. From what I can tell this is also a test-only cleanup. Given that review in this project is scarce and that there are around 400 other pull requests open for review, I'm closing this for now.