Test that IpNeighborMonitor is stopped when IpServer stops.

Bug: 159097215
Test: test-only change
Original-Change: https://android-review.googlesource.com/1343441
Merged-In: I2292c1cbff06a304f70191b88d833b19af2b8b92
Change-Id: I2292c1cbff06a304f70191b88d833b19af2b8b92
diff --git a/Tethering/tests/unit/src/android/net/ip/IpServerTest.java b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
index c65069c..30a9d22 100644
--- a/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
+++ b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
@@ -860,6 +860,7 @@
         verify(mBpfCoordinator).tetherOffloadRuleClear(mIpServer);
         verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighA, macA));
         verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighB, macB));
+        verify(mIpNeighborMonitor).stop();
         resetNetdAndBpfCoordinator();
     }