message: Do not remove the validity mask for block valid when finalizing
  This prevents us from rolling back the chain and reconsidering
  blocks on a new chain.
diff: @@ -1353,7 +1353,6 @@ CBlockIndex *FindMostWorkChain()
  pindexNew->GetBlockHash().ToString(), pindexFinalized->nHeight);
  pindexNew->nStatus |= BLOCK_FAILED_VALID;
  - pindexNew->nStatus &= ~BLOCK_VALID_CHAIN;
  }
  // Check whether all blocks on the path between the currently active chain and the candidate are valid.
  