[amd64] Avoid passing the pc/pc offset to the throw corlib exception trampoline in...

[amd64] Avoid passing the pc/pc offset to the throw corlib exception trampoline in llvm mode, instead simply use the return address pushed by the call itself. In JIT mode, this is needed because the throw code is generated out of line so its not inside the try range, but in llvm mode, the try-range encompasses the call.