[Perf-training] Using os.devnull instead of a temp file
[Perf-training] Using os.devnull instead of a temp file

This is based on post-commit feedback from Vedant. Totally didn't know that existed and worked on Windows.

Thanks Vedant!

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@264064 91177308-0d34-0410-b5e6-96231b3b80d8

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