Execution tree of a single test method has unexpected root name

It looks like it actually uses some kind of default `toString()` method than something that should be a label (e.g. name of the Testclass).

```
Eclipse SDK

Version: 2025-12 (4.38)
Build id: I20251027-1800
```

Reproduce the execution tree for a single test method in Eclipse SDK 2025-12 and inspect how the root label is chosen. Compare the current default toString()-style name with the expected test-class label; the issue is done when the root displays a meaningful label consistently.

Written by the indexing model from the issue text.