[llvm] [WebAssembly] Disallow tail calls with byval arguments (PR #125142)

[Thomas Lively via llvm-commits]

tlively wrote:

Thanks for the references, @efriedma-quic. I don't quite understand the thing about copying via a temporary slot, but I don't think it applies to WebAssembly because we always copy to a fresh stack slot. My mental model for how this works may be wrong, though.

https://github.com/llvm/llvm-project/pull/125142