DO NOT MERGE: Enable mainline prebuilts for device targets am: 20545fcf am: a047ea2b

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/23770789



Change-Id: I61335352118772d2abcf5a3e01597a16a9552792
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>