[llvm] [InstCombine] add restrict reassoc for the powi(X, Y) / X (PR #86428)

[via llvm-commits]

github-actions[bot] wrote:

<!--LLVM CODE FORMAT COMMENT: {darker}-->

:white_check_mark: With the latest revision this PR passed the Python code formatter.

https://github.com/llvm/llvm-project/pull/86428