Add cts for EthernetManager#getInterfaceList api.

Bug: 171872016
Test: atest android.net.cts.EthernetManagerTest --iterations
Merged-In: I95a21777689fd100ccf94982d3398418036b674f
Change-Id: I46a2b26ca1a5846523aed94bc9744e11daa39859
1 file changed