[clang] [clang][CodeGen] Emit prefetch hints and frame address depth as i32 (PR #221477)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

For `__builtin_returnaddress`, the argument type is explicitly "int"; I guess converting it makes sense given the required form for LLVM.

For `__builtin_prefetch`, it looks like we're just not doing any conversions at all in Sema, which is wrong; SemaChecking should be doing lvalue-to-rvalue conversion, and converting to some reasonable type.  I guess at that point, if the chosen type is `int`, you still end up needing to do a conversion on some targets, but still, I'd like to fix it while we're looking at this.

https://github.com/llvm/llvm-project/pull/221477