Add build files for Mobly lib am: 8b4837b237 am: d0d77c4902

Original change: https://android-review.googlesource.com/c/platform/external/python/mobly/+/2113566

Change-Id: I86cec228796501234448b569e88e5c9c3a02292e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>