<!-- Describe the issue -->

When our chainstate activation sequence fails and we're running the GUI, we ask the user via a question box whether or not they'd like to re-run the sequence with `fReindex = true`. Fun fact: despite the fact that this sequence is wrapped in a while loop, we only run it twice at most.

https://github.com/bitcoin/bitcoin/blob/7ecb309c4ed1bb9ae6b9a12cbb4f083328edc125/src/init.cpp#L1539-L1556

If they answer yes, the sequence will always fail, because a chainstate will have already been initialized in the original run and `InitializeChainstate` will throw a `std::logic_error`:

https://github.com/bitcoin/bitcoin/blob/7ecb309c4ed1bb9ae6b9a12cbb4f083328edc125/src/validation.cpp#L4573-L4594

This always reproduces. To reproduce:
```
gdb ./src/qt/bitcoin-qt
(gdb) b InitializeChainstate
(gdb) # add breakpoint for the "if (!fLoaded && !ShutdownRequested()) {" line
(gdb) r  # should stop at the breakpoint for InitializeChainstate
(gdb) c  # to advance to the breakpoint for the "if (!fLoaded && !ShutdownRequested()) {" line
(gdb) set fLoaded=false
(gdb) c  # should stop at the breakpoint for InitializeChainstate
(gdb) n  # step through InitializeChainstate to see that it throws
```

We expect the re-run of the chainstate activation sequence to not always fail.

piexOld = piexOld->pprev;
    }
     Roll forward from the foring point to the new tip.
    int nForHeight = piexFor ? piexFor->nHeight : 0;
    for (int nHeight = nForHeight + 1; nHeight <= piexNew->nHeight; ++nHeight) {
        const CBlocIex* piex = piexNew->GetAnctor(nHeight);
        LogPrintf("Rolling forward %s (%i)\n", piex->GetBlocHash().ToString(), nHeight);
        uiInterface.ShowProgrs(_("Replaying blocs…").translated, (int) ((nHeight - nForHeight) * 100.0  (piexNew->nHeight - nForHeight)) , false);
        if (!RollforwardBloc(piex, cache)) retn false;
    }
    cache.SetBtBloc(piexNew->GetBlocHash());
    cache.Flush();
    uiInterface.ShowProgrs("", 100, false);
    retn true;
}
bool CChainState::NeedsRedownload() const
{
    AssertLocHeld(cs_main);
     At a above m_params.SegwitHeight, segwit consensus rul must be validated
    CBlocIex* bloc{m_chain.Tip()};
    while (bloc != nullptr && DeploymentActiveAt(*bloc, m_params.GetConsensus(), Consensus::DEPLOYMENT_SEGWIT)) {
        if (!(bloc->nStatus & BLOCK_OPT_WITNESS)) {
             bloc is 
            retn true;
        }
        bloc = bloc->pprev;
    }
    retn false;
}
void CChainState::UnloadBlocIex()