Add build_matrix_runner.sh for automated testing am: f6a0f23045 am: 42ff40385f Original change: https://googleplex-android-review.googlesource.com/c/kernel/tests/+/41911489 Change-Id: I11ba332b5633edbc104edfb37372eb33d3d42370 Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>