Auto merge of #86419 - ricobbe:raw-dylib-stdcall, r=petrochenkov

Auto merge of #86419 - ricobbe:raw-dylib-stdcall, r=petrochenkov

Add support for raw-dylib with stdcall, fastcall functions

Next stage of work for #58713: allow `extern "stdcall"` and `extern "fastcall"` with `#[link(kind = "raw-dylib")]`.

I've deliberately omitted support for vectorcall, as that doesn't currently work, and I wanted to get this out for review.  (I haven't really investigated the vectorcall failure much yet, but at first (very cursory) glance it appears that the problem is elsewhere.)