[llvm] [dsymutil] Filter our swiftinterface files from the toolchain. (PR #71205)

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dyung wrote:

> I made an attempt to fix this here:
> 
> commit [2d460f2](https://github.com/llvm/llvm-project/commit/2d460f25f14db38e566810040806c95f9edd78b5) (HEAD -> main) Author: Adrian Prantl [aprantl at apple.com](mailto:aprantl at apple.com) Date: Fri Nov 3 18:26:22 2023 -0700
> 
> ```
> Attempt to fix test on Windows.
> 
> I'm assuming that because sys::path::append defaults to native path
> this fails. Since dsymutil is a Darwin tool, we can just hardcode the
> UNIX path separator.
> ```

That looks like it did the trick (https://lab.llvm.org/buildbot/#/builders/216/builds/29804), thanks!

https://github.com/llvm/llvm-project/pull/71205