[llvm] [llvm-dwarfdump] Make --verify for .debug_names multithreaded. (PR #127281)

[Alexander Yermolovich via llvm-commits]

ayermolo wrote:

To add.
As a followup we can refactor:

```
void OutputCategoryAggregator::Report(
    StringRef s, std::function<void(void)> detailCallback) {
  std::lock_guard<std::mutex> Lock(WriteMutex);
  ++NumErrors;
  Aggregation[std::string(s)]++;
  if (IncludeDetail)
    detailCallback();
}
```
So that category is an enum.
We can then turn Aggregation into a vector, of vectors.
Where second vector will be some generic/compact data structure, that callback would know how to set.
We can then print all the categories after everything was processed. 
Just an idea.

https://github.com/llvm/llvm-project/pull/127281