This broke the coverage tool, as material/animated_icons/animated_icons.dart
was loaded twice as a part, once directly animated_icons_private_test, and one
through animated_icons_private_test->flutter_tester->...->material
The coverage package assumes a 1:1 mapping between VM scripts and URIs due to a
limitation in the underlying vm_service_client package, which currently doesn't
provide a unique identifier for VM scripts.
The underlying issue is tracked by dart-lang/coverage#194.
9ed652d042