Switch TestNetworkStack to release API

Instead of building TestNetworkStack against the in-development SDK,
use the latest released SDK.

This allows TestNetworkStack to build in mainline branches, where the
in-development SDK may not be available.
TestNetworkStack is used for install/rollback testing, so using a
release-like build instead of a development build makes the test more
realistic.

Change-Id: Ia72af6cffe6c34bb93db3147b8ee201b36eb359a
Test: m
Bug: 175609674