Disable prebuilts when building with clang coverage am: f372ce14

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/18601940



Change-Id: I9c2e484728e2299a17c5ee0a145a304e84610848
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>