Calling `*txoutset` calls in the console has been broken since #19056. The addition of the `RpcInterruptionPoint()` calls means that any user running the GUI without passing `-server`, will just see ["Shutting down"](https://github.com/bitcoin/bitcoin/blob/b33136b6ba9887f7db651c4c5264ca7f2f601df7/src/rpc/server.cpp#L325) printed to the console:

![console](https://user-images.githubusercontent.com/863730/84460760-55599a80-ac9d-11ea-8720-a718edde75dd.png)

cc @MarcoFalke 
{
private:
    bool m_could_reserve;
public:
    explicit CoinsViewScanReserver() : m_could_reserve(false) {}
    bool reserve() {
        CHECK_NONFATAL(!m_could_reserve);
        if (g_scan_in_progress.exchange(true)) {
            return false;
        }
        m_could_reserve = true;
        return true;
    }
    ~CoinsViewScanReserver() {