[llvm] [NFC] Add fragment-getting functions to DbgRecord (PR #97705)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-aarch64-rel-assert` running on `linaro-flang-aarch64-rel-assert` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/29/builds/851

Here is the relevant piece of the build log for the reference:
```
Step 5 (build-unified-tree) failure: build (failure)

```

https://github.com/llvm/llvm-project/pull/97705