When test interface are no longer tracked in ethernet, clear out
associated data. Besides polluting the dumpsys and taking up
memory, unexpected results could happen if other CTS tests or
the like were to use a test interface which happened to have an
existing configuration for it (i.e., the tests could fail). This is more
problematic since IP configuration data is written to disc, therefore
test data was being persisted across reboots.
Bug: 210485380
Bug: 210487893
Test: atest EthernetServiceTests
atest CtsNetTestCases
Change-Id: If85c625ebbf8da27b226d9ae3651c4fb83a9a8da
53d2a2c414