Extract test utilities for ConnectivityService

The utilities help using ConnectivityService in tests, and will be used
to write integration tests for ConnectivityService.

Test: atest FrameworksNetTests
Change-Id: Ie895ad05139cd5768d3d8a9bd5589d72571f47e6
diff --git a/tests/net/Android.bp b/tests/net/Android.bp
index 5260b30..502aa97 100644
--- a/tests/net/Android.bp
+++ b/tests/net/Android.bp
@@ -56,6 +56,7 @@
         "androidx.test.rules",
         "FrameworksNetCommonTests",
         "frameworks-base-testutils",
+        "frameworks-net-integration-testutils",
         "framework-protos",
         "mockito-target-minus-junit4",
         "net-tests-utils",