[llvm] [Bitcode][NFC] Add abbrev for FUNC_CODE_DEBUG_LOC (PR #146497)

[Jeremy Morse via llvm-commits]

jmorse wrote:

Merged in 51f4e2cda2b3af853734b83aa523063afdd7bd46 , as discussed I think the size-cost is worth it, and it sounds like we'll gain it back with the additional abbrevs anyway.

https://github.com/llvm/llvm-project/pull/146497