[llvm] Add option to dump IR to files instead of stderr (PR #66412)

[Sebastian Neubauer via llvm-commits]

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@@ -0,0 +1,57 @@
+; RUN: mkdir -p %t/logs
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Flakebi wrote:

Is the `mkdir` needed?
On Linux, `rm -rf` ignores missing directories, not sure about Windows.

https://github.com/llvm/llvm-project/pull/66412