Add unit tests for Tethering.isTetherProvisioningRequired

Check that we tolerate various dependencies not being available.

Bug: 31946071
Test: These are tests

Change-Id: Ic0a9cd6f255ba9ff4c774dee640df1a0bdf8dc39
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index f16376d..97b0981 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -128,6 +128,7 @@
 import com.android.server.am.BatteryStatsService;
 import com.android.server.connectivity.DataConnectionStats;
 import com.android.server.connectivity.KeepaliveTracker;
+import com.android.server.connectivity.MockableSystemProperties;
 import com.android.server.connectivity.Nat464Xlat;
 import com.android.server.connectivity.NetworkAgentInfo;
 import com.android.server.connectivity.NetworkDiagnostics;
@@ -760,7 +761,8 @@
         mTestMode = SystemProperties.get("cm.test.mode").equals("true")
                 && SystemProperties.get("ro.build.type").equals("eng");
 
-        mTethering = new Tethering(mContext, mNetd, statsService, mPolicyManager);
+        mTethering = new Tethering(mContext, mNetd, statsService, mPolicyManager,
+                                   IoThread.get().getLooper(), new MockableSystemProperties());
 
         mPermissionMonitor = new PermissionMonitor(mContext, mNetd);