We now get lots of compile time output like:
```bash
In file included from test/fuzz/addition_overflow.cpp:7:
./test/fuzz/util.h: In member function 'virtual SOCKET FuzzedSock::Get() const':
./test/fuzz/util.h:563:5: warning: no return statement in function returning non-void [-Wreturn-type]
  563 |     }
      |     ^
./test/fuzz/util.h: In member function 'virtual SOCKET FuzzedSock::Release()':
./test/fuzz/util.h:568:5: warning: no return statement in function returning non-void [-Wreturn-type]
  568 |     }
      |     ^
...
```
anywhere `test/fuzz/util.h` is included. Would be great to not have build logs filled with this spam.

This was all present in the CI. i.e https://cirrus-ci.com/task/5500626558779392?command=ci#L4283. 

cc @practicalswift @vasild 
 const SOCKET socket = INVALID_SOCKET;
    const CAddress address = ConsumeAddress(fuzzed_data_provider);
    const uint64_t keyed_net_group = fuzzed_data_provider.ConsumeIntegral<uint64_t>();
    const uint64_t local_host_nonce = fuzzed_data_provider.ConsumeIntegral<uint64_t>();
    const CAddress addr_bind = ConsumeAddress(fuzzed_data_provider);
    const std::string addr_name = fuzzed_data_provider.ConsumeRandomLengthString(64);
    const ConnectionType conn_type = fuzzed_data_provider.PickValueInArray(ALL_CONNECTION_TYPES);
    const bool inbound_onion{conn_type == ConnectionType::INBOUND ? fuzzed_data_provider.ConsumeBool() : false};
    if constexpr (ReturnUniquePtr) {
        return std::make_unique<CNode>(node_id, local_services, socket, address, keyed_net_group, local_host_nonce, addr_bind, addr_name, conn_type, inbound_onion);
    } else {
        return CNode{node_id, local_services, socket, address, keyed_net_group, local_host_nonce, addr_bind, addr_name, conn_type, inbound_onion};
    }
}
inline std::unique_ptr<CNode> ConsumeNodeAsUniquePtr(FuzzedDataProvider& fdp, const std::optional<NodeId>& node_id_in = std::nullopt) { return ConsumeNode<true>(fdp, node_id_in); }
void FillNode(FuzzedDataProvider& fuzzed_data_provider, CNode& node, bool init_version) noexcept;
class FuzzedFileProvider
{
    FuzzedDataProvider& m_fuzzed_data_provider;
    int64_t m_offset = 0;
public:
    FuzzedFileProvider(FuzzedDataProvider& fuzzed_data_provider) : m_fuzzed_data_provider{fuzzed_data_provider}
    {
    }
    FILE* open()
    {
        if (m_fuzzed_data_provider.ConsumeBool()) {
            return nullptr;
        }
        std::string mode;
        CallOneOf(
            m_fuzzed_data_provider,
            [&] {
                mode = "r";
            },
            [&] {
                mode = "r+";
            },
            [&] {
                mode = "w";
            },
            [&] {
                mode = "w+";
            },
            [&] {
             