[llvm] IVDescriptors: cut wasteful FAnyOf checking (NFC) (PR #118393)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> This effectively makes FAnyOf dead, right? In that case it should be removed and `IAnyOf` -> `AnyOf`?

There is still FAnyOf matching with FCmp, and IAnyOf matching with ICmp, so I don't think it can be removed. See getReductionOpChain's call to getOpcode for example.

https://github.com/llvm/llvm-project/pull/118393