<!-- 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.

{
    return pa->nHeight < pb->nHeight;
}
static FILE* OpenUndoFile(const FlatFilePos& pos, bool fReadOnly = false);
static FlatFileSeq BlockFileSeq();
static FlatFileSeq UndoFileSeq();
std::vector<CBlockIndex*> BlockManager::GetAllBlockIndices()
{
    AssertLockHeld(cs_main);
    std::vector<CBlockIndex*> rv;
    rv.reserve(m_block_index.size());
    for (auto& [_, block_index] : m_block_index) {
        rv.push_back(&block_index);
    }
    return rv;
}
CBlockIndex* BlockManager::LookupBlockIndex(const uint256& hash)
{
    AssertLockHeld(cs_main);
    BlockMap::iterator it = m_block_index.find(hash);
    return it == m_block_index.end() ? nullptr : &it->second;
}
const CBlockIndex* BlockManager::LookupBlockIndex(const uint256& hash) const
{
    AssertLockHeld(cs_main);
    BlockMap::const_iterator it = m_block_index.find(hash);
    return it == m_block_index.end() ? nullptr : &it->second;
}
CBlockIndex* BlockManager::AddToBlockIndex(const CBlockHeader& block, CBlockIndex*& best_header)