Migrate shell-as to platform_testing/utils am: 4be0618c85 am: cf4751eaea am: 0107274cfe am: 1bd9373301 am: 2ad26f8de3 am: f0294420c8

Original change: https://googleplex-android-review.googlesource.com/c/platform/platform_testing/+/24165379

Change-Id: I66047de6027e72e3b105d20a8d8b0b9ed6fb194d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>