Re-exports :flags dep from flags/testing, so that unit tests don't have to import it themselves.
Re-exports :flags dep from flags/testing, so that unit tests don't have to import it themselves.

PiperOrigin-RevId: 344147275

PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs