Lookup private resources in run-time

This fixes the following cases for us:

android.net.cts.ConnectivityManagerTest#testGetAllNetworkInfo
android.net.cts.ConnectivityManagerTest#testGetNetworkInfo
android.net.cts.ConnectivityManagerTest#testIsNetworkSupported
android.net.cts.ConnectivityManagerTest#testRequestRouteToHost
android.net.cts.ConnectivityManagerTest#testSetNetworkPreference

We need to use the prebuilt binary but that has dependency to
private resource identities that differs in our environment. With
this change the resources are looked up in run-time to avoid the
build time dependency.

Change-Id: I6579338b591ca7a0da3f03f796136269c7789780