`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.
#include <addrman.h>
#include <amount.h>
#include <banman.h>
#include <blockfilter.h>
#include <chain.h>
#include <chainparams.h>
#include <compat/sanity.h>
#include <fs.h>
#include <hash.h>
#include <httprpc.h>
#include <httpserver.h>
#include <index/blockfilterindex.h>
#include <index/txindex.h>
#include <init/common.h>
#include <interfaces/chain.h>
#include <interfaces/node.h>
#include <mapport.h>
#include <miner.h>
#include <net.h>
#include <net_permissions.h>
#include <net_processing.h>
#include <netbase.h>
#include <node/blockstorage.h>
#include <node/context.h>
#include <node/ui_interface.h>
#include <policy/feerate.h>
#include <policy/fees.h>
#include <policy/policy.h>
#include <policy/settings.h>
#include <protocol.h>