Merge "Move the ART prebuilt update script to a location outside the ART sources." am: 6aa3ac0cff

Original change: https://android-review.googlesource.com/c/platform/packages/modules/ArtPrebuilt/+/1580584

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ic3f2139234dd5da32a2f2d7705f999f52c1eb281