When downloading and running Bitcoin core for the first time, after clicking through the "Are you sure you want to open. it?" screen, there's a possibility that macOS will pass an argument like `-psn_0_SOME_ID` to the application, which results in a shutdown as it's an invalid argument:

![v0 19 0rc1 args shutdown](https://user-images.githubusercontent.com/863730/67034964-b026fc00-f0e6-11e9-8462-70d0fcf613e6.png)

This only happens on the first run, subsequent opens will work fine, but we should filter these out, otherwise it's a poor and confusing first experience.

{
    if (IsArgNegated(strArg)) return true; 
    return ArgsManagerHelper::GetArg(*this, strArg).first;
}
bool ArgsManager::IsArgNegated(const std::string& strArg) const
{
    LOCK(cs_args);
    const auto& ov = m_override_args.find(strArg);
    if (ov != m_override_args.end()) return ov->second.empty();
    if (!m_network.empty()) {
        const auto& cfs = m_config_args.find(ArgsManagerHelper::NetworkArg(*this, strArg));
        if (cfs != m_config_args.end()) return cfs->second.empty();
    }
    const auto& cf = m_config_args.find(strArg);
    if (cf != m_config_args.end()) return cf->second.empty();
    return false;
}
std::string ArgsManager::GetArg(const std::string& strArg, const std::string& strDefault) const