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

[via llvm-commits]

dyung wrote:

Hi @adrian-prantl, the test you added `tools/dsymutil/X86/swift-interface.test` seems to be failing on Windows hosts. Can you take a look and revert if you need time to investigate?

https://lab.llvm.org/buildbot/#/builders/117/builds/16428
https://lab.llvm.org/buildbot/#/builders/216/builds/29793
https://lab.llvm.org/buildbot/#/builders/233/builds/4060
https://lab.llvm.org/buildbot/#/builders/235/builds/2976

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