I think that if a reorg fails due to an error while disconnecting blocks, the node should shut down.

My thought is that if we are trying to switch to a more work chain and something goes wrong before we can even try to validate that more-work chain, then we have a problem that is not related to the chain we're trying to switch to but instead related to our own hardware or software; shutting down and having the user deal with the issue is better than continuing on, when we know there's a more work chain that we're unable to try validating.

This has recently come up on testnet, where unpatched nodes are unable to reorg from the invalid chain containing the duplicate-input-in-a-transaction block, but rather than crash or shutdown they are continuing on the invalid chain, with messages like this in the debug log:

```
ERROR: DisconnectTip(): DisconnectBlock 00000000210004840364b52bc5e455d888f164e4264a4fec06a514b67e9d5722 failed
```
} while (!chainActive.Tip() || (starting_tip && CBlockIndexWorkComparator()(chainActive.Tip(), starting_tip)));
            if (!blocks_connected) return true;
            const CBlockIndex* pindexFork = chainActive.FindFork(starting_tip);
            bool fInitialDownload = IsInitialBlockDownload();
            
            
            if (pindexFork != pindexNewTip) {
                
                GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, fInitialDownload);
                
                uiInterface.NotifyBlockTip(fInitialDownload, pindexNewTip);
            }
        }
        
        if (nStopAtHeight && pindexNewTip && pindexNewTip->nHeight >= nStopAtHeight) StartShutdown();
        
        
        
        
        if (ShutdownRequested())
            break;
    } while (pindexNewTip != pindexMostWork);
    CheckBlockIndex(chainparams.GetConsensus());
    
    if (!FlushStateToDisk(chainparams, state, FlushStateMode::PERIODIC)) {
        return false;
    }
    return true;
}
bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock) {