Stop tracking left-over test interfaces

When setIncludeTestInterfaces(false) is called, any RTM_DELLINK
callback for a testtap interface is ignored, since the interface is no
longer considered to be a valid ethernet interface.

Change setIncludeTestInterfaces to go through all interfaces, and stop
tracking the ones which are no longer valid. Otherwise, they will
stick around forever (and break subsequent tests).

Bug: 390722214
Test: TH
Change-Id: Ied73e86c0452831f4d6b00f67908c51201af8bbd
2 files changed