[libcxx-commits] [libcxx] [llvm] [libc++][CI] Add a Github workflow to test libc++ tools (PR #211067)

[Louis Dionne via libcxx-commits]

ldionne wrote:

> Do we need a new dedicated GitHub workflow for this or can we add it to the existing libc++ workflow?
> 
> https://github.com/llvm/llvm-project/blob/18220e793fbda204b66c08989cde11ad4583f26c/.github/workflows/libcxx-build-and-test.yaml#L88

We can, but we'd have to use

```
fetch-depth: 0 # some tools need full git history
fetch-tags: true
```

on all the jobs of the same stage (unless we want to make things more complicated). If you still think this is better, I can do that, but my thinking was actually to split up workflows that do fundamentally different things since our main `build-and-test` workflow has gotten fairly large.

https://github.com/llvm/llvm-project/pull/211067