Merge "Only allow .scl files to load other .scl files" into main am: 7c8607715d am: f85e863d75 am: a93dbae471

Original change: https://android-review.googlesource.com/c/platform/build/+/2820037

Change-Id: I61038de633a859f5fab5143cf83323657c1c3c3d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>