Cleanup SBOM test script for later adding tests of generating SBOM of am: 1b2badc4

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/soong/+/24029572



Change-Id: Ied0621a8bf73e53768d0f7e8f11841223c69f88f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>