[llvm] [LLVM] Add `llvm.experimental.vector.compress` intrinsic (PR #92289)

[Luke Lau via llvm-commits]

https://github.com/lukel97 approved this pull request.

Can't speak for the GlobalISel/AArch64 stuff but the LangRef + SelectionDAG parts LGTM, thanks! Probably best if you wait for another LGTM.

https://github.com/llvm/llvm-project/pull/92289