Tweak NetworkWatchListTests.

Add logging to try to help diagnose flakiness.

And while I'm here, simplify & improve file closing logic.

Bug: 168216494
Test: atest CtsNetTestCases:android.net.cts.NetworkWatchlistTest
Change-Id: I1c875102f0cce32cbbe2e3b36de913741c9abb92
1 file changed
tree: c80cbad36fad43be9924287c3b90f19c9381c506
  1. tests/
  2. Tethering/