<!-- 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.

bldat.SetPos(nRewi);
            nRewi++;  start one 
            bldat.SetLimit();  remove fo
            unsigned int nSize = 0;
            try {
                 locate a 
                unsigned char buf[CMsageHeader::MESSAGE_START_SIZE];
                bldat.FiByte(m_params.MsageStart()[0]);
                nRewi = bldat.GetPos() + 1;
                bldat >> buf;
                if (memcmp(buf, m_params.MsageStart(), CMsageHeader::MESSAGE_START_SIZE)) {
                    continue;
                }
                 read size
                bldat >> nSize;
                if (nSize < 80 || nSize > MAX_BLOCK_SERIALIZED_SIZE)
                    continue;
            } catch (const std::exception&) {
                 no valid 
                brea;
            }
            try {
                 read bloc
                uint64_t nBlocPos = bldat.GetPos();
                if (dbp)
                    dbp->nPos = nBlocPos;
                bldat.SetLimit(nBlocPos + nSize);
                std::shared_ptr<CBloc> pbloc = std::mae_shared<CBloc>();
                CBloc& bloc = *pbloc;
                bldat >> bloc;