android.net.lowpan: Added basic unit tests.

This change has all of the bits for supporting LoWPAN unit tests.
Additional tests are being written to improve code coverage, but this
seems like a good start.

Bug: b/33073713
Test: Successfully ran enclosed unit tests
Change-Id: Ib3750be5052bf1a90bf871756e9121b047d3871f
diff --git a/lowpan/tests/AndroidManifest.xml b/lowpan/tests/AndroidManifest.xml
new file mode 100644
index 0000000..a216214
--- /dev/null
+++ b/lowpan/tests/AndroidManifest.xml
@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright (C) 2017 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
+  -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="android.net.lowpan.test">
+
+    <application>
+        <uses-library android:name="android.test.runner" />
+        <activity android:label="LowpanTestDummyLabel"
+                  android:name="LowpanTestDummyName">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+    </application>
+
+    <instrumentation android:name="android.support.test.runner.AndroidJUnitRunner"
+        android:targetPackage="android.net.lowpan.test"
+        android:label="Frameworks LoWPAN API Tests">
+    </instrumentation>
+
+</manifest>