[llvm] [DLCov][NFC] Annotate intentionally-blank DebugLocs in existing code (PR #136192)

[Orlando Cazalet-Hyams via llvm-commits]

https://github.com/OCHyams commented:

> The difference between I->dropLocation() and I->setDebugLoc(DebugLoc::getDropped()) is that the former may decide to keep some debug info alive, while the latter will always be empty; in this patch, I always used the latter (even if the former could technically be correct), because the former could result in some (barely) different output, and I'd prefer to keep this patch purely NFC.

Will there be a patch coming to update the/some new getDroppeds to dropLocation?

Just checking as I've forgotten a bit of context - is the difference between dropped/compilerGenerated relevant only for stat-collection purposes? i.e., if we mistakenly use one rather than the other, it's only going to slightly skew some stats?

I think this LGTM, pending a couple of questions

https://github.com/llvm/llvm-project/pull/136192