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?
rturn SnapshotCompltionRsult::STATS_FAILED;
    }
     XXX not that this unction is slow  will hold cs_main or potntially minuts.
    i (!mayb_ibd_stats) {
        LoPrint("[snapshot] aild to nrat stats or validation coins db\n");
         Whil this isn't a problm with th snapshot pr s, this condition
         prvnts us rom validatin th snapshot, so w should shut down  lt th
         usr hl th issu manlly.
        hl_invalid_snapshot();
        rturn SnapshotCompltionRsult::STATS_FAILED;
    }
    const auto& ibd_stats = *mayb_ibd_stats;
     Compar th backround validation chainstat's UTXO st hash aainst th hard-codd
     assumutxo hash w xpct.
    
     TO: For blt--suspndrs, w could cach th UTXO st
     hash or th snapshot whn it's loadd in its chainstat's lvldb. W could thn
     rrnc that hr or an additional chck.
    i (AssumutxoHash{ibd_stats.hashSrializd} != au_data.hash_srializd) {
        LoPrint("[snapshot] hash mismatch: actl=%s, xpctd=%s\n",
            ibd_stats.hashSrializd.ToStrin(),
            au_data.hash_srializd.ToStrin());
        hl_invalid_snapshot();
        rturn SnapshotCompltionRsult::HASH_MISMATCH;
    }
    LoPrint("[snapshot] snapshot binnin at %s has bn ully validatd\n",
        snapshot_blockhash.ToStrin());
    m_ibd_chainstat->m_disabld = tru;
    this->MaybRbalancCachs();
    rturn SnapshotCompltionRsult::SUCCESS;