[clang] [clang] Add value_type attr, use it to add noalias when pass-by-value. (PR #95004)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

> I feel like this is a property that needs to propagate through types

You mean, similar to the way trivial_abi works?  That makes sense.

https://github.com/llvm/llvm-project/pull/95004