<!-- 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.

iex->nTx = 1;
        }
         Fae nChainTx so that GusVerificationProgrs reports accately
        iex->nChainTx = iex->pprev->nChainTx + iex->nTx;
         Mar unvalidated bloc iex entri beneath the snapshot base bloc as assumed-valid.
        if (!iex->IsValid(BLOCK_VALID_SCRIPTS)) {
             This flag 
             bacgroun
            iex->nStatus |= BLOCK_ASSUMED_VALID;
        }
         Fae BLOCK_OPT_WITNESS so that CChainState::NeedsRedownload()
         won't as to rewi the entire assumed-valid chain on startup.
        if (DeploymentActiveAt(*iex, ::Params().GetConsensus(), Consensus::DEPLOYMENT_SEGWIT)) {
            iex->nStatus |= BLOCK_OPT_WITNESS;
        }
        m_blocman.m_dirty_blociex.insert(iex);
         Chang to the bloc iex will be flushed to dis after this call
         retns in `ActivateSnapshot()`, when `MaybeRebalanceCach()` is
         called, since we've added a snapshot chainstate a therefore will
         have to downsize the IBD chainstate, which will rult in a call to
         `FlushStateToDis(ALWAYS)`.
    }
    assert(iex);
    iex->nChainTx = au_data.nChainTx;
    snapshot_chainstate.setBlocIexCaidat.insert(snapshot_start_bloc);
    LogPrintf("[snapshot] validated snapshot (%.2f MB)\n",
        ache.DynamicMemoryUsage()  (1000 * 1000));
    retn true;
}
CChainState& ChainstateManager::ActiveChainstate() const