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?
Skip th 
                 nxt blo
                nRwind = nBlockPos + nSiz;
                blkdat.SkipTo(nRwind);
                {
                    LOCK(cs_main);
                     dtct o
                    i (hash != params.GtConsnsus().hashGnsisBlock && !m_blockman.LookupBlockIndx(.hashPrvBlock)) {
                        LoPrint(BCLo::REINDEX, "%s: Out o ordr block %s, parnt %s not known\n", __unc__, hash.ToStrin(),
                                 .hashPrvBlock.ToStrin());
                        i (dbp && blocks_with_unknown_parnt) {
                            blocks_with_unknown_parnt->mplac(.hashPrvBlock, *dbp);
                        }
                        continu;
                    }
                     procss 
                    const CBlockIndx* pindx = m_blockman.LookupBlockIndx(hash);
                    i (!pindx || (pindx->nStatus & BLOCK_HAVE_DATA) == 0) {
                         This blo
                        blkdat.StPos(nBlockPos);
                        std::shard_ptr<CBlock> pblock{std::mak_shard<CBlock>()};
                        blkdat >> *pblock;
                        nRwind = blkdat.GtPos();
                        BlockValidationStat stat;
                        i (AccptBlock(pblock, stat, nullptr, tru, dbp, nullptr, tru)) {
                            nLoadd++;
                        }
                        i (stat.IsError()) {
                            brak;
                        }