Split NetworkStackUtils to frameworks/libs/net

Split DeviceConfig and collections-related utilities to CollectionUtils
and DeviceConfigUtils in frameworks/libs/net.

Also add implementations for contains(array, value), to avoid usage of
internal non-API utils.

The original tests are based on mockito-extended, so also add to
NetworkStackTests as a dependency. This also requires setting the test
app as debuggable in its manifest.

Bug: 17454103
Test: atest NetworkStaticLibTests
Change-Id: Ie9bed66a08b7370ebe50d0a7240b788f8b31aa77
diff --git a/staticlibs/tests/unit/AndroidManifest.xml b/staticlibs/tests/unit/AndroidManifest.xml
index c747c8a..84a20a2 100644
--- a/staticlibs/tests/unit/AndroidManifest.xml
+++ b/staticlibs/tests/unit/AndroidManifest.xml
@@ -19,7 +19,7 @@
 
     <uses-permission android:name="android.permission.INTERNET" />
 
-    <application>
+    <application android:debuggable="true">
         <uses-library android:name="android.test.runner" />
     </application>