message: Fix blockencoding unit test error
diff: @@ -52,12 +52,12 @@ public:
  }
  }
  - uint16_t offset = 0;
  + int32_t offset = 0;
  for (size_t j = 0; j < indexes.size(); j++) {
  - if (uint64_t(indexes[j]) + uint64_t(offset) > std::numeric_limits<uint16_t>::max())
  + if (int32_t(indexes[j]) + offset > std::numeric_limits<uint16_t>::max())
  throw std::ios_base::failure("indexes overflowed 16 bits");
  indexes[j] = indexes[j] + offset;
  - offset = indexes[j] + 1;
  + offset = int32_t(indexes[j]) + 1;
  }
  } else {
  for (size_t i = 0; i < indexes.size(); i++) {
  @@ -186,6 +186,9 @@ public:
  READWRITE(prefilledtxn);
  + if (BlockTxCount() > std::numeric_limits<uint16_t>::max())
  + throw std::ios_base::failure("indexes overflowed 16 bits");
  +
  if (ser_action.ForRead())
  FillShortTxIDSelector();
  }
  