[Thread] add service unit test skeleton

Adds the Thread service unit test skeleton and make the services
testable.

Initially, a few trivial unit tests for existing APIs are added in
ThreadNetworkControllerServiceTest.java, and more tests will be added in
separate CLs later.

Bug: 317555104
Change-Id: I7b9e5f3663493d8da2448568de792e4272ee1df6
diff --git a/thread/tests/unit/AndroidTest.xml b/thread/tests/unit/AndroidTest.xml
index 597c6a8..26813c1 100644
--- a/thread/tests/unit/AndroidTest.xml
+++ b/thread/tests/unit/AndroidTest.xml
@@ -30,5 +30,8 @@
         <option name="hidden-api-checks" value="false"/>
         <!-- Ignores tests introduced by guava-android-testlib -->
         <option name="exclude-annotation" value="org.junit.Ignore"/>
+        <!-- Ignores tests introduced by frameworks-base-testutils -->
+        <option name="exclude-filter" value="android.os.test.TestLooperTest"/>
+        <option name="exclude-filter" value="com.android.test.filters.SelectTestTests"/>
     </test>
 </configuration>