Unexpected Inspector behavior with package roots

In this screenshot:

- I am running the `standalone_ui/editor_sidebar` run configuration in the devtools_app project.
- I used the inspector & select widget mode to select the column in the mock editor (from `mock_editor_widget.dart`)
- In the summary tree, nothing below the `SizedBox` widget from the `SplitPane` is present.
- In the details tree, the Column I have selected is present.
- The `mock_editor_widget.dart` file exists under `devtools_app/test/` and one of the pub root directories is `/Users/path/to/devtools_app`, so widgets created in this location should be included in the summary tree.