Fix flaky testNattSocketKeepalives

The test did not wait for the WifiNetworkAgent to disconnect, and there
are reports of flakes where it is still connected in
connectKeepaliveNetwork.

Test: atest FrameworksNetTests
Bug: 124319553
Change-Id: I85968806885c8853ec4f4dbea356366c1af0ea1c
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index 1548a76..a191744 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -3791,11 +3791,14 @@
     }
 
     @Test
-    public void testNattSocketKeepalives() throws Exception {
+    public void testNattSocketKeepalives_SingleThreadExecutor() throws Exception {
         final ExecutorService executorSingleThread = Executors.newSingleThreadExecutor();
         doTestNattSocketKeepalivesWithExecutor(executorSingleThread);
         executorSingleThread.shutdown();
+    }
 
+    @Test
+    public void testNattSocketKeepalives_InlineExecutor() throws Exception {
         final Executor executorInline = (Runnable r) -> r.run();
         doTestNattSocketKeepalivesWithExecutor(executorInline);
     }
@@ -3937,6 +3940,7 @@
         testSocket2.close();
 
         mWiFiNetworkAgent.disconnect();
+        waitFor(mWiFiNetworkAgent.getDisconnectedCV());
     }
 
     @Test