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 
   return j < (std::numeric_limits<T>::min() / i);
            }
        } else {
            if (j > 0) {
                return i < (std::numeric_limits<T>::min() / j);
            } else {
                return i != 0 && (j < (std::numeric_limits<T>::max() / i));
            }
        }
    } else {
        return j != 0 && i > std::numeric_limits<T>::max() / j;
    }
}
template <class T>
[[nodiscard]] bool AdditionOverflow(const T i, const T j) noexcept
{
    static_assert(std::is_integral<T>::value, "Integral required.");
    if (std::numeric_limits<T>::is_signed) {
        return (i > 0 && j > std::numeric_limits<T>::max() - i) ||
               (i < 0 && j < std::numeric_limits<T>::min() - i);
    }
    return std::numeric_limits<T>::max() - i < j;
}
[[nodiscard]] inline bool ContainsSpentInput(const CTransaction& tx, const CCoinsViewCache& inputs) noexcept
{
    for (const CTxIn& tx_in : tx.vin) {
        const Coin& coin = inputs.AccessCoin(tx_in.prevout);
        if (coin.IsSpent()) {
            return true;
        }
    }
    return false;
}
/**
 * Sets errno to a value selected from the given std::array `errnos`.
 */
template <typename T, size_t size>
void SetFuzzedErrNo(FuzzedDataProvider& fuzzed_data_provider, const std::array<T, size>& errnos)
{
    errno = fuzzed_data_provider.PickValueInArray(errnos);
}
/**
 * Returns a byte vector of specified size regardless of the number of remaining bytes available
 * from the fuzzer. Pads with zero value bytes if needed to achieve the specified size.
 */
[[nodiscard]] inline std::vector<uint8_t> ConsumeFixedLengthByteVector(FuzzedDataProvider& fuzzed_data_provider, const size_t length) noexcept
{
    std::vector<uint8_t> result(length);
    const std::vector<uint8_t> random_bytes = fuzzed_data_provider.ConsumeBytes<uint8_t>(length);
    if (!random_bytes.empty()) {
        std::memcpy(result.data(), random_bytes.data(), random_bytes.size());
    }
    return result;
}
inline CNetAddr ConsumeNetAddr(FuzzedDat