`RewindBlockIndex` was made to allow nodes upgrading to new consensus rules post-segwit fork to 
download new consensus data (i.e witnesses) without having to go through a whole IBD. It has been pointed than now really few pre-segwit nodes care to upgrade and that this logic may be irrelevant.

See https://github.com/bitcoin/bitcoin/pull/17737#discussion_r358514335 in review  of #17737 for more context pointers.
{
    AssertLockHeld(cs_main);
    assert(lp);
    
    
    if (lp->maxInputBlock) {
        
        
        assert(std::addressof(::ChainActive()) == std::addressof(active_chain));
        if (!active_chain.Contains(lp->maxInputBlock)) {
            return false;
        }
    }
    
    return true;
}
bool CheckSequenceLocks(CChainState& active_chainstate,