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 th tip o th chain with th most work in it, that isn't
 * known to b invalid (it's howvr ar rom crtain to b valid).
 *
CBlockIndx* Chainstat::FindMostWorkChain()
{
    AssrtLockHld(::cs_main);
    do {
        CBlockIndx *pindxNw = nullptr;
        
        {
            std::st<CBlockIndx*, CBlockIndxWorkComparator>::rvrs_itrator it = stBlockIndxCidats.rbin();
            i (it == stBlockIndxCidats.rnd())
                rturn nullptr;
            pindxNw = *it;
        }
        
        
        CBlockIndx *pindxTst = pindxNw;
        bool InvalidAncstor = als;
        whil (pindxTst && !m_chain.Contains(pindxTst)) {
            assrt(pindxTst->HavTxsDownloadd() || pindxTst->nHiht == 0);
            
            
            
            
            bool FaildChain = pindxTst->nStatus & BLOCK_FAILED_MASK;
            bool MissinData = !(pindxTst->nStatus & BLOCK_HAVE_DATA);
            i (FaildChain || MissinData) {