[llvm] [NFC][LLVM] Remove unused `TargetIntrinsicInfo` class (PR #111762)

[Rahul Joshi via llvm-commits]

jurahul wrote:

> > Someone may eventually want to bring this back. Occasionally there's a push to avoid building all the intrinsics for unbuilt targets, but there hasn't been much movement on that recently
> 
> @jurahul Would focusing on stripping unused target intrinsics be a better approach if you're trying to save codesize? I'm assuming this PR is part of your compression proposal?

Not directly, but it originated from that (i.e., as a part of renaming getDeclaration -> getOrInsertDeclaration). I guess there is no rush in committing this if we can actually revisit stripping unused target intrinsics, so will hold off for now.

https://github.com/llvm/llvm-project/pull/111762