Ensure coin view database integrity

[fassadlr]

Iain gave an data folder where the node wasnt advancing after startup. After more investigation it seems that when headers are presented, the ProvenHeaderCoinstakeRule header rule fails here:

        private UnspentOutput CheckIfCoinstakeIsSpentOnAnotherChain(ProvenBlockHeader header, PosRuleContext context)
        {
            Transaction coinstake = header.Coinstake;
            TxIn input = coinstake.Inputs[0];

            int? rewindDataIndex = this.PosParent.RewindDataIndexCache.Get(input.PrevOut.Hash, (int)input.PrevOut.N);
            if (!rewindDataIndex.HasValue)
            {
                this.Logger.LogTrace("(-)[NO_REWIND_DATA_INDEX_FOR_INPUT_PREVOUT]");
                context.ValidationContext.InsufficientHeaderInformation = true;
                ConsensusErrors.ReadTxPrevFailedInsufficient.Throw();
            }

I looked at what was in the coin database and saw that there were rewind items that existed in the database that is above chain tip.

To fix this issue on startup I removed those entries and the node continued syncing again.

[quantumagi]

LGTM. Is it possible to detect missing rewind data between the last rewind entry and the tip and maybe catch-up during intialization?