Enable self-testing by default in rkp factory tool am: ed854b2b3b

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/security/+/23501328

Change-Id: Ia00ed30ebd0b8cf9f074c6dbd8a2ff0a747b3e99
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>