[llvm] [IR] Add llvm `clmul` intrinsic (PR #140301)

[Craig Topper via llvm-commits]

topperc wrote:

> Tests appear to be passing locally. Is this good to go?

There are no tests for any of the legalization or expansion code. There are only tests for when the clmul instruction is supported.

https://github.com/llvm/llvm-project/pull/140301