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

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

Suppose you have a function like `void g(S, S); void f(S a, S b) { return g(b, a); }`.  To tail-call, you have to essentially swap a and b.  You use a temporary to avoid overwriting the argument before you copy it.

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