Merge "Don't build targets if they're not used." into main am: 1ef9d680 am: 14f6de4a

Original change: https://android-review.googlesource.com/c/platform/build/+/3204820



Change-Id: Ib4071d41a9c7ecdb103346284f01eace8d9b82e8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>