[clang] [CIR] Preserve const pointee information on function params (PR #218114)

[Andy Kaylor via cfe-commits]

andykaylor wrote:

> Hey, Should we close this PR, as there is not consumer we could write for this attribute?

Probably so? I can imagine this being useful, but without an actual user it's hard to make a case for having it implemented.

https://github.com/llvm/llvm-project/pull/218114