[llvm] [llvm] Make TestData compatible with c++20 (PR #143801)

[Paul Kirth via llvm-commits]

ilovepi wrote:

### Merge activity

* **Jun 12, 3:21 PM UTC**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/143801).


https://github.com/llvm/llvm-project/pull/143801