On my Linux Mint 19.1:
```bash
$ umask
0022
```

After the first run of `bitcoin-qt -sysperm=false` the `0700` permissions are expected for both the datadir (`~/.bitcoin`) and the walletdir (`~/.bitcoin/wallets`).

Actually, the directories are created with such access permissions:
```bash
$ stat ~/.bitcoin | grep Uid
Access: (0755/drwxr-xr-x)  Uid: ( 1000/ hebasto)   Gid: ( 1000/ hebasto)
$ stat ~/.bitcoin/wallets | grep Uid
Access: (0755/drwxr-xr-x)  Uid: ( 1000/ hebasto)   Gid: ( 1000/ hebasto)
```

Refs:
- #4286
- #13371
- #13389

NOTE: reading through the initial PR #4286 makes me think it was controversial. Is it a better and simpler way to just get rid of `-sysperm` option? I believe a user who needs this option can easily run `chown` command.
{
    return AbsPathForConfigVal(args.GetPathArg("-pid", BITCOIN_PID_FILENAME));
}
[[nodiscard]] static bool CreatePidFile(const ArgsManager& args)
{
    std::ofstream file{GetPidFile(args)};
    if (file) {
#ifdef WIN32
        tfm::format(file, "%d\n", GetCurrentProcessId());
#else
        tfm::format(file, "%d\n", getpid());
#endif
        return true;
    } else {
        return InitError(strprintf(_("Unable to create the PID file '%s': %s"), fs::PathToString(GetPidFile(args)), SysErrorString(errno)));
    }
}
#if HAVE_SYSTEM
static void ShutdownNotify(const ArgsManager& args)
{
    std::vector<std::thread> threads;
    for (const auto& cmd : args.GetArgs("-shutdownnotify")) {
        threads.emplace_back(runCommand, cmd);
    }
    for (auto& t : threads) {
        t.join();
    }
}
#endif
void Interrupt(NodeContext& node)