[llvm] [AsmPrinter][DebugNames] Implement DW_IDX_parent entries (PR #77457)

[David Blaikie via llvm-commits]

https://github.com/dwblaikie commented:

Few minor bits of feedback (except the bit twiddling thing - that's one I think is especially worth some more attention/better ergonomics)

https://github.com/llvm/llvm-project/pull/77457