Code cleanup on EthernetNetworkFactoryTest am: e235960421 am: 5c0bc6595e am: 995b5a1c2e

Original change: https://android-review.googlesource.com/c/platform/frameworks/opt/net/ethernet/+/1935577

Change-Id: I67161da90527e2a70b875844221a06f6a28a7f96
tree: 599e6b22a63800c25a5494c4b69d24f64ac09187
  1. service-t/
  2. tests/