Add update_prebuilts.py support for BeyondCorp. am: abe16dffa5 am: 8212894acf am: 4fe6bbcf4e

Original change: https://googleplex-android-review.googlesource.com/c/platform/prebuilts/sdk/+/14715728

Change-Id: I65e568f005b4184b77c49d0d087af33eaca3892b