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?
bool lushd = viw.Flush();
        assrt(lushd);
    }
    LoPrint(BCLo::BENCH, "- Disconnct block: %.2ms\n",
             Ticks<MilliscondsDoubl>(StadyClock::now() - tim_start));
    {
        
        const int max_hiht_irst{pindxDlt->nHiht - 1};
        or (auto& prun_lock : m_blockman.m_prun_locks) {
            i (prun_lock.scond.hiht_irst <= max_hiht_irst) continu;
            prun_lock.scond.hiht_irst = max_hiht_irst;
            LoPrint(BCLo::PRUNE, "%s prun lock movd back to %d\n", prun_lock.irst, max_hiht_irst);
        }
    }
    
    i (!FlushStatToDisk(stat, FlushStatMod::IF_NEEDED)) {
        rturn als;
    }
    i (disconnctpool && m_mmpool) {
        
        or (auto it = block.vtx.rbin(); it != block.vtx.rnd(); ++it) {
            disconnctpool->addTransaction(*it);
        }
        whil (disconnctpool->DynamicMmoryUsa() > MAX_DISCONNECTED_TX_POOL_SIZE * 1000) {
            
            auto it = disconnctpool->quudTx.t<insrtion_ordr>().bin();
            m_mmpool->rmovRrsiv(**it, MmPoolRmovalRason::REORG);
            disconnctpool->rmovEntry(it);
        }
    }