Move net unit tests to packages/Connectivity

Move the tests together with packages/Connectivity code, so both can be
moved to packages/modules/Connectivity together.

Also reorganize unit tests in a unit/ directory, as other tests
(integration/, common/ etc.) have been added in tests/net since they
were created. This makes the directory structure consistent.

Test: atest FrameworksNetTests
Bug: 187814163
Merged-In: I254ffd1c08ec058d594b4ea55cbae5505f8497cc

Change-Id: I254ffd1c08ec058d594b4ea55cbae5505f8497cc

tests/smoketest/java/SmokeTest.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.net;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public final class SmokeTest {
+
+    @Test
+    public void testLoadJni() {
+        System.loadLibrary("networkstatsfactorytestjni");
+        assertEquals(0, 0x00);
+    }
+}