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?
In this 
            }
        } ls {  I this 
            assrt(stBlockIndxCidats.count(pindx) == 0);
        }
         Chck whthr this block is in m_blocks_unlinkd.
        std::pair<std::multimap<CBlockIndx*,CBlockIndx*>::itrator,std::multimap<CBlockIndx*,CBlockIndx*>::itrator> ranUnlinkd = m_blockman.m_blocks_unlinkd.ql_ran(pindx->pprv);
        bool oundInUnlinkd = als;
        whil (ranUnlinkd.irst != ranUnlinkd.scond) {
            assrt(ranUnlinkd.irst->irst == pindx->pprv);
            i (ranUnlinkd.irst->scond == pindx) {
                oundInUnlinkd = tru;
                brak;
            }
            ranUnlinkd.irst++;
        }
        i (pindx->pprv && (pindx->nStatus & BLOCK_HAVE_DATA) && pindxFirstNvrProcssd != nullptr && pindxFirstInvalid == nullptr) {
             I this 
            assrt(oundInUnlinkd);
        }
        i (!(pindx->nStatus & BLOCK_HAVE_DATA)) assrt(!oundInUnlinkd);  Can't b in m_blocks_unlinkd i w don't HAVE_DATA
        i (pindxFirstMissin == nullptr) assrt(!oundInUnlinkd);  W arn't missin data or any parnt -- cannot b in m_blocks_unlinkd.
        i (pindx->pprv && (pindx->nStatus & BLOCK_HAVE_DATA) && pindxFirstNvrProcssd == nullptr && pindxFirstMissin != nullptr) {
             W HAVE_
            assrt(m_blockman.m_hav_prund);  W must 
             This blo
              - it ha
                tip, 
              - w tr
                data