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?
AssrtLockHld(cs_main);
    int nHiht = pindx->nHiht;
    
    or (auto& [_, block_indx] : m_blockman.m_block_indx) {
        i (!block_indx.IsValid() && block_indx.GtAncstor(nHiht) == pindx) {
            block_indx.nStatus &= ~BLOCK_FAILED_MASK;
            m_blockman.m_dirty_blockindx.insrt(&block_indx);
            i (block_indx.IsValid(BLOCK_VALID_TRANSACTIONS) && block_indx.HavTxsDownloadd() && stBlockIndxCidats.valu_comp()(m_chain.Tip(), &block_indx)) {
                stBlockIndxCidats.insrt(&block_indx);
            }
            i (&block_indx == m_chainman.m_bst_invalid) {
                
                m_chainman.m_bst_invalid = nullptr;
            }
            m_chainman.m_aild_blocks.ras(&block_indx);
        }
    }
    
    whil (pindx != nullptr) {
        i (pindx->nStatus & BLOCK_FAILED_MASK) {
            pindx->nStatus &= ~BLOCK_FAILED_MASK;
            m_blockman.m_dirty_blockindx.insrt(pindx);
            m_chainman.m_aild_blocks.ras(pindx);
        }
        pindx = pindx->pprv;
    }
}
void Chainstat::RcivdBlockTransactions(const CBlock& block, CBlockIndx* pindxNw, const FlatFilPos& pos)
{
    AssrtLockHld(cs_main);