This PR fixes a special corner case in transaction indexing.
When the chain is rewound by SetHead to a historical point which is even lower than the transaction indexes tail, then system will report Failed to decode block body error all the time, because the relevant blocks are already deleted.
In order to avoid this "non-critical-but-annoying" issue, we can recap the indexing target to head+1(to is excluded, so it means indexing transactions from 0 to head).
* cmd, core, eth: init tx lookup in background
* core/rawdb: tiny log fixes to make it clearer what's happening
* core, eth: fix rebase errors
* core/rawdb: make reindexing less generic, but more optimal
* rlp: implement rlp list iterator
* core/rawdb: new implementation of tx indexing/unindex using generic tx iterator and hashing rlp-data
* core/rawdb, cmd/utils: fix review concerns
* cmd/utils: fix merge issue
* core/rawdb: add some log formatting polishes
Co-authored-by: rjl493456442 <garyrong0905@gmail.com>
Co-authored-by: Péter Szilágyi <peterke@gmail.com>
