message: validation: Use existing chain member in CChainState::AcceptBlock
diff: @@ -3682,8 +3682,9 @@ bool CChainState::AcceptBlock(const std::shared_ptr<const CBlock>& pblock, Block
  // Write block to history file
  if (fNewBlock) *fNewBlock = true;
  + assert(std::addressof(::ChainActive()) == std::addressof(m_chain));
  try {
  - FlatFilePos blockPos = SaveBlockToDisk(block, pindex->nHeight, ::ChainActive(), chainparams, dbp);
  + FlatFilePos blockPos = SaveBlockToDisk(block, pindex->nHeight, m_chain, chainparams, dbp);
  if (blockPos.IsNull()) {
  state.Error(strprintf("%s: Failed to find position to write new block to disk", __func__));
  return false;
  