[llvm] [Reassociate] Drop weight reduction to fix issue 91417 (PR #91469)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> Should we even keep the test cases then if this unused transform is gonna be removed anyway?

Yes. IIRC these tests are useful to some mutation-based fuzzers.


https://github.com/llvm/llvm-project/pull/91469