[llvm] [DebugInfo] Assign best possible debugloc to bundle (PR #164573)

[Orlando Cazalet-Hyams via llvm-commits]

https://github.com/OCHyams commented:

>From a debug info perspective I don't have a good handle on what's best to do with a bundle, but I've got some general patch feedback.

I think the test could be minimised a little more? e.g.
* remove `#dbg_value`s
* looks like there's many `!dbg` / `DILocations` that are not needed
* the whole llc pipeline is run; can this be narrowed down to a specific pass using `--start-before` `--stop-after`?

https://github.com/llvm/llvm-project/pull/164573