Add warning signs for directories that contains files where results were produced

At present, only files are being shown with warning icons. It'd be nice to show warning icon to the parent directories of the affected files too.

The issue does not name a file or test. Start by locating the Angular view or component that renders warning icons for affected files, then trace how the directory tree is built. Done means parent directories containing affected files also display warning icons, with existing file warnings still working.

Written by the indexing model from the issue text.