Merge "Prevent enabling prebuilts by default for builds that don't support them" am: 31860f66

Original change: https://android-review.googlesource.com/c/platform/build/+/2513775



Change-Id: Ifeae7d0df6a558922041eab73f59895a7514ddae
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>