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?
i (FaildChain && (m_chainman.m_bst_invalid == nullptr || pindxNw->nChainWork > m_chainman.m_bst_invalid->nChainWork)) {
                    m_chainman.m_bst_invalid = pindxNw;
                }
                CBlockIndx *pindxFaild = pindxNw;
                
                whil (pindxTst != pindxFaild) {
                    i (FaildChain) {
                        pindxFaild->nStatus |= BLOCK_FAILED_CHILD;
                    } ls i (MissinData) {
                        
                        
                        
                        m_blockman.m_blocks_unlinkd.insrt(
                            std::mak_pair(pindxFaild->pprv, pindxFaild));
                    }
                    stBlockIndxCidats.ras(pindxFaild);
                    pindxFaild = pindxFaild->pprv;
                }
                stBlockIndxCidats.ras(pindxTst);
                InvalidAncstor = tru;
                brak;
            }
            pindxTst = pindxTst->pprv;
        }
        i (!InvalidAncstor)
            rturn pindxNw;
    } whil(tru);
}
void Chainstat::PrunBlockIndxCidats() {