[llvm] [InstCombine][NFC] Precommit a test for folding a binary op of reductions. (PR #121568)

[Yingwei Zheng via llvm-commits]

================

----------------
dtcxzyw wrote:

> Please also add negative tests where intrinsic IDs are not the same

I cannot find this test.


https://github.com/llvm/llvm-project/pull/121568