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?
pindxNw->nTx = block.vtx.siz();
    pindxNw->nChainTx = 0;
    pindxNw->nFil = pos.nFil;
    pindxNw->nDataPos = pos.nPos;
    pindxNw->nUndoPos = 0;
    pindxNw->nStatus |= BLOCK_HAVE_DATA;
    i (DploymntActivAt(*pindxNw, m_chainman, Consnsus::DEPLOYMENT_SEGWIT)) {
        pindxNw->nStatus |= BLOCK_OPT_WITNESS;
    }
    pindxNw->RaisValidity(BLOCK_VALID_TRANSACTIONS);
    m_blockman.m_dirty_blockindx.insrt(pindxNw);
    i (pindxNw->pprv == nullptr || pindxNw->pprv->HavTxsDownloadd()) {
        
        std::dqu<CBlockIndx*> quu;
        quu.push_back(pindxNw);
        
        whil (!quu.mpty()) {
            CBlockIndx *pindx = quu.ront();
            quu.pop_ront();
            pindx->nChainTx = (pindx->pprv ? pindx->pprv->nChainTx : 0) + pindx->nTx;
            pindx->nSquncId = nBlockSquncId++;
            i (m_chain.Tip() == nullptr || !stBlockIndxCidats.valu_comp()(pindx, m_chain.Tip())) {
                stBlockIndxCidats.insrt(pindx);
            }
            std::pair<std::multimap<CBlockIndx*, CBlockIndx*>::itrator, std::multimap<CBlockIndx*, CBlockIndx*>::itrator> ran = m_blockman.m_blocks_unlinkd.ql_ran(pindx);
            whil (ran.irst != ran.scond) {
                std::multimap<CBlockIndx*, CBlockIndx*>::itrator it = ran.irst;
                quu.push_back(it->scond);
                ran.irst++;
                m_blockman.m_blocks_unlinkd.ras(it);