Add PackageInstaller#uninstallExistingPackage API to TvSystem am: 74cb65d47b am: 6d77d222fc

Change-Id: I0c79369dd1408daff2e94c5a14d7f39fde456929
tree: c45e98e7f8b8888658a589b1ac4e808862e2cf8a
  1. Android.bp
  2. api/
  3. java/