[llvm] [Coverage] Mark coverage sections as metadata sections on COFF. (PR #76834)

[Arthur Eubanks via llvm-commits]

aeubanks wrote:

I don't think it makes sense to put this in the IR, choosing when emitting an object file seems like the right place to make this decision

this looks in line with existing SectionKind overrides per object file format (e.g. `getELFKindForNamedSection`, `TargetLoweringObjectFileWasm::getExplicitSectionGlobal`). `TargetLoweringObjectFile::getKindForGlobal()` is where the common logic is, and there's an argument to be made to consolidate all of the per object file format overrides into that method, but I also think this is fine

https://github.com/llvm/llvm-project/pull/76834