Add Tests for EthernetNetworkFactory am: 4a60d53369 am: d8eeaf4bd3

Original change: https://android-review.googlesource.com/c/platform/frameworks/opt/net/ethernet/+/1486182

Change-Id: Id09046b501b7b280830e51d5b82f2d5e8f7fa6d7
tree: 82501b274b4859d3bcf1d3c5ad49f7071dc9dc7f
  1. service-t/
  2. tests/