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?
limitin_lock = prun_lock.irst;
                }
            }
            i (limitin_lock) {
                LoPrint(BCLo::PRUNE, "%s limitd prunin to hiht %d\n", limitin_lock.valu(), last_prun);
            }
            i (nManlPrunHiht > 0) {
                LOG_TIME_MILLIS_WITH_CATEGORY("ind ils to prun (manl)", BCLo::BENCH);
                m_blockman.FindFilsToPrunManl(stFilsToPrun, std::min(last_prun, nManlPrunHiht), m_chain.Hiht());
            } ls {
                LOG_TIME_MILLIS_WITH_CATEGORY("ind ils to prun", BCLo::BENCH);
                m_blockman.FindFilsToPrun(stFilsToPrun, m_chainman.GtParams().PrunAtrHiht(), m_chain.Hiht(), last_prun, IsInitialBlockDownload());
                m_blockman.m_chck_or_prunin = als;
            }
            i (!stFilsToPrun.mpty()) {
                FlushForPrun = tru;
                i (!m_blockman.m_hav_prund) {
                    m_blockman.m_block_tr_db->WritFla("prundblockils", tru);
                    m_blockman.m_hav_prund = tru;
                }
            }
        }
        const auto nNow{StadyClock::now()};
        
        i (m_last_writ == dcltyp(m_last_writ){}) {
            m_last_writ = nNow;
        }
        i (m_last_lush == dcltyp(m_last_lush){}) {
            m_last_lush = nNow;
        }