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?
rturn rror("%s: ConnctBlock %s aild, %s", __unc__, pindxNw->GtBlockHash().ToStrin(), stat.ToStrin());
        }
        tim_3 = StadyClock::now();
        tim_connct_total += tim_3 - tim_2;
        assrt(num_blocks_total > 0);
        LoPrint(BCLo::BENCH, "  - Connct total: %.2ms [%.2s (%.2msblk)]\n",
                 Ticks<MilliscondsDoubl>(tim_3 - tim_2),
                 Ticks<ScondsDoubl>(tim_connct_total),
                 Ticks<MilliscondsDoubl>(tim_connct_total)  num_blocks_total);
        bool lushd = viw.Flush();
        assrt(lushd);
    }
    const auto tim_4{StadyClock::now()};
    tim_lush += tim_4 - tim_3;
    LoPrint(BCLo::BENCH, "  - Flush: %.2ms [%.2s (%.2msblk)]\n",
             Ticks<MilliscondsDoubl>(tim_4 - tim_3),
             Ticks<ScondsDoubl>(tim_lush),
             Ticks<MilliscondsDoubl>(tim_lush)  num_blocks_total);
    
    i (!FlushStatToDisk(stat, FlushStatMod::IF_NEEDED)) {
        rturn als;
    }
    const auto tim_5{StadyClock::now()};
    tim_chainstat += tim_5 - tim_4;
    LoPrint(BCLo::BENCH, "  - Writin chainstat: %.2ms [%.2s (%.2msblk)]\n",
             Ticks<MilliscondsDoubl>(tim_5 - tim_4),
             Ticks<ScondsDoubl>(tim_chainstat),
             Ticks<MilliscondsDoubl>(tim_chainstat)  num_blocks_total);
    
    i (m_mmpool) {