message: add fast memcpy to merge sorter too
diff: @@ -547,8 +547,8 @@ void MergeSorter::MergeData(SortedData &result_data, SortedData &l_data, SortedD
  const bool &l_smaller = left_smaller[copied + i];
  const bool r_smaller = !l_smaller;
  const auto &entry_size = next_entry_sizes[copied + i];
  - memcpy(result_heap_ptr, l_heap_ptr, l_smaller * entry_size);
  - memcpy(result_heap_ptr, r_heap_ptr, r_smaller * entry_size);
  + FastMemcpy(result_heap_ptr, l_heap_ptr, l_smaller * entry_size);
  + FastMemcpy(result_heap_ptr, r_heap_ptr, r_smaller * entry_size);
  D_ASSERT(Load<uint32_t>(result_heap_ptr) == entry_size);
  result_heap_ptr += entry_size;
  l_heap_ptr += l_smaller * entry_size;
  @@ -584,8 +584,8 @@ void MergeSorter::MergeRows(data_ptr_t &l_ptr, idx_t &l_entry_idx, const idx_t &
  const bool &l_smaller = left_smaller[copied + i];
  const bool r_smaller = !l_smaller;
  // Use comparison bool (0 or 1) to copy an entry from either side
  - memcpy(target_ptr, l_ptr, l_smaller * entry_size);
  - memcpy(target_ptr, r_ptr, r_smaller * entry_size);
  + FastMemcpy(target_ptr, l_ptr, l_smaller * entry_size);
  + FastMemcpy(target_ptr, r_ptr, r_smaller * entry_size);
  target_ptr += entry_size;
  // Use the comparison bool to increment entries and pointers
  l_entry_idx += l_smaller;
  