Have Fast Sanity as a Distro Feature Instead of manually adding flags per platform, we can just do a distro feature instead Tested: fast sanity is built when adding distro feature fusion2:N/A Google-Bug-Id: 428023363 Change-Id: Ic4f0f73247669c54c9d4c8bbd770c0ed3c125155 Signed-off-by: Edward Lee <edwarddl@google.com>