Memory leak due to no stop for IpNeighborMonitor. am: 93e59ee726

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11910263

Change-Id: I22a5b3526c32c989be5c0fc644e9f177b8fe2eac

Tethering/src/android/net/ip/IpServer.java

@@ -1322,6 +1322,7 @@ public class IpServer extends StateMachine {
     class UnavailableState extends State {
         @Override
         public void enter() {
+            mIpNeighborMonitor.stop();
             mLastError = TetheringManager.TETHER_ERROR_NO_ERROR;
             sendInterfaceState(STATE_UNAVAILABLE);
         }