Merge "Remove an NPE in tearDown" into main am: e7b7ceb7

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2770460



Change-Id: I017eafbc7dcf191cf6babcd3c43fa89a66546bbc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

tests/cts/hostside/app/src/com/android/cts/net/hostside/AbstractRestrictBackgroundNetworkTestCase.java

@@ -199,7 +199,8 @@ public abstract class AbstractRestrictBackgroundNetworkTestCase {
     protected void tearDown() throws Exception {
         executeShellCommand("cmd netpolicy stop-watching");
         mServiceClient.unbind();
-        if (mLock.isHeld()) mLock.release();
+        final PowerManager.WakeLock lock = mLock;
+        if (null != lock && lock.isHeld()) lock.release();
     }
 
     protected int getUid(String packageName) throws Exception {