[llvm] [InstCombine] Fold tan(x) * cos(x) => sin(x) (PR #136319)

[Yingwei Zheng via llvm-commits]

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+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
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dtcxzyw wrote:

Missing test for the commuted case `cos * tan` and a negative test with mismatched `X` (i.e. `tan(a) * cos(b)`).


https://github.com/llvm/llvm-project/pull/136319