[llvm] [BinaryFormat] Add "SFrame" structures and constants (PR #147264)

[Pavel Labath via llvm-commits]

labath wrote:

> In the patch, I've used the naming convention for everything that has a direct equivalent to the specification (modulo changing macros to constants), and used the llvm convention for everything else.

I think this will be the most controversial part of the patch. Starting out, it made sense to me to use the original convention, but the more code I write using this, the less I am convinced that is the right choice. I can find precedents for both choices in the codebase. I'd be happy to LLVM-ify this code if that is preferred.

https://github.com/llvm/llvm-project/pull/147264