Function test_reach_for_changed_paths 

pub fn test_reach_for_changed_paths(
    graph: &RetainedModuleGraph,
    root: &Path,
    changed_exports: &[ChangedExport],
    is_test_path: &dyn Fn(&str) -> bool,
) -> Option<TestReachPaths>

Classify how tests reach the value exports in changed_exports.

Type-only exports, re-exports, exports of test files, of declaration files and of stylesheets are skipped. is_test_path classifies a root-relative, forward-slashed path; a test entry point always counts as a test file. The rows keep the order of changed_exports. None when the list holds no such export.