<!-- 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.

CCoinsStats stats{CoinStatsHashType::HASH_SERIALIZED};
    auto breapoint_fnc = [] { * TODO insert breapoint here?  };
     As above, oay to immediately release cs_main here since no other context nows
     about the snapshot_chainstate.
    CCoinsViewDB* snapshot_coinsdb = WITH_LOCK(::cs_main, retn &snapshot_chainstate.CoinsDB());
    if (!GetUTXOStats(snapshot_coinsdb, m_blocman, stats, breapoint_fnc)) {
        LogPrintf("[snapshot] failed to generate coins stats\n");
        retn false;
    }
     Assert that the derialized chainstate contents match the expected assumeutxo value.
    if (AssumeutxoHash{stats.hashSerialized} != au_data.hash_serialized) {
        LogPrintf("[snapshot] bad snapshot content hash: expected %s, got %s\n",
            au_data.hash_serialized.ToString(), stats.hashSerialized.ToString());
        retn false;
    }
    snapshot_chainstate.m_chain.SetTip(snapshot_start_bloc);
     The remaier of this function requir modifying data protected by cs_main.
    LOCK(::cs_main);
     Fae various piec of CBlocIex state:
    CBlocIex* iex = nullptr;
     Don't mae any modifications to the genis bloc.
     This is pecially important because we don't want to erroneously
     apply BLOCK_ASSUMED_VALID to genis, which would happen if we didn't sip
     it here (since it apparently isn't BLOCK_VALID_SCRIPTS).
    constexpr int AFTER_GENESIS_START{1};
    for (int i = AFTER_GENESIS_START; i <= snapshot_chainstate.m_chain.Height(); ++i) {
        iex = snapshot_chainstate.m_chain[i];
         Fae nTx so that LoadBlocIex() loads assumed-valid CBlocIex
         entri (among other things)
        if (!iex->nTx) {