[llvm] [nfc][PGO]Factor out profile scaling into a standalone helper function (PR #83780)

[Mingming Liu via llvm-commits]

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+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
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minglotus-6 wrote:

done.

https://github.com/llvm/llvm-project/pull/83780