Fix flaky NsdManagerTest

There is a race condition between socket connection succeeding
and interface returning a non-empty address list. So verify
that interface returns a non-empty list, before trying the
socket connection.

Bug: 272147547
Test: atest android.net.cts.NsdManagerTest --iteration 10
Change-Id: I7c7a03688ad6d8d76c741a99eeb74d28933986f1
1 file changed