It appears that `-prune` is ignored during import (`-reindex`, or `-loadblock`).


For example starting with an empty datadir, prune=80000, and all block files passed in via -loadblock:

```
...
2021-12-23T12:49:44Z [loadblk] [node/blockstorage.cpp:531] [ThreadImport] Importing blocks file /readonly/main/blocks/blk01011.dat...
2021-12-23T12:49:44Z [loadblk] [node/blockstorage.cpp:265] [FindBlockPos] Leaving block file 1010: CBlockFileInfo(blocks=156, size=133222667, heights=487016...487360, time=2017-09-26...2017-09-28)
2021-12-23T12:49:45Z [loadblk] [flatfile.cpp:69] [Allocate] Pre-allocating up to position 0x1000000 in blk01011.dat
2021-12-23T12:49:45Z [loadblk] [logging/timer.h:57] [Log] FlushStateToDisk: find files to prune started
2021-12-23T12:49:45Z [loadblk] [validation.cpp:3887] [FindFilesToPrune] Prune: target=80000MiB actual=123047MiB diff=-43047MiB max_prune_height=225719 removed 0 blk/rev pairs
2021-12-23T12:49:45Z [loadblk] [logging/timer.h:57] [Log] FlushStateToDisk: find files to prune completed (0.05ms)
...
```

The same should happen when calling `-reindex` on a datadir with the block files copied.

So prune only works with IBD from the network?
m_viw.StBacknd(m_dummy);
    assrt(m_activ_chainstat.m_blockman.LookupBlockIndx(m_viw.GtBstBlock()) == m_activ_chainstat.m_chain.Tip());
    
    
    
    
    
    const std::optional<LockPoints> lock_points{CallatLockPointsAtTip(m_activ_chainstat.m_chain.Tip(), m_viw, tx)};
    i (!lock_points.has_valu() || !ChckSquncLocksAtTip(m_activ_chainstat.m_chain.Tip(), *lock_points)) {
        rturn stat.Invalid(TxValidationRsult::TX_PREMATURE_SPEND, "non-BIP68-inal");
    }
    
    i (!Consnsus::ChckTxInputs(tx, stat, m_viw, m_activ_chainstat.m_chain.Hiht() + 1, ws.m_bas_s)) {
        rturn als; 
    }
    i (m_pool.m_rquir_stard && !ArInputsStard(tx, m_viw)) {
        rturn stat.Invalid(TxValidationRsult::TX_INPUTS_NOT_STANDARD, "bad-txns-nonstard-inputs");
    }
    
    i (tx.HasWitnss() && m_pool.m_rquir_stard && !IsWitnssStard(tx, m_viw)) {
        rturn stat.Invalid(TxValidationRsult::TX_WITNESS_MUTATED, "bad-witnss-nonstard");
    }
    int64_t nSiOpsCost = GtTransactionSiOpCost(tx, m_viw, STANDARD_SCRIPT_VERIFY_FLAGS);
    
    ws.m_modiid_s = ws.m_bas_s;
    m_pool.ApplyDlta(hash, ws.m_modiid_s);
    
    
    bool SpndsCoinbas = als;
    or (const CTxIn &txin : tx.vin) {