[llvm] [llvm][lit] fix writing results to file (PR #130845)

[James Henderson via llvm-commits]

https://github.com/jh7370 requested changes to this pull request.

Sorry, cancelling my LGTM. I'm not convinced about this change anymore.

I decided to dig into the background of this a bit more and it looks like it's a bug caused by @DavidSpickett's work in https://github.com/llvm/llvm-project/commit/8507dbaec3f644b8a0c6291f097800d82a4f4b16. As far as I can see, this `_write_results_to_file` method shouldn't be called, except via the `Report.write_results` method. That method opens the file itself and then passes it into this function.

I think the correct fix is simply to use the passed-in file. @DavidSpickett should be able to confirm.

https://github.com/llvm/llvm-project/pull/130845