[clang] [clang] put EmitParmDecl in the target-requested AS (PR #181256)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

Okay, that makes sense.  Let me know if you want feedback on the wasm thing, but probably whatever you come up with is fine.

https://github.com/llvm/llvm-project/pull/181256