Add more powerful CTS for allowedUids

This tests that the network providers are subject to appropriate
limitations as to what they can set as allowedUids – both in the
positive (can do) case, and the negative (can't do) case.

Test: this
Change-Id: I115e2a4bc02ddcd03ecf2f35130fcb0378da22bd

tests/unit/java/com/android/server/ConnectivityServiceTest.java

@@ -17386,6 +17386,7 @@ public class ConnectivityServiceTest {
         mCm.requestNetwork(new NetworkRequest.Builder()
                         .clearCapabilities()
                         .addTransportType(TRANSPORT_TEST)
+                        .addTransportType(TRANSPORT_CELLULAR)
                         .build(),
                 cb);