DO NOT MERGE: Add androidx prebuilt TEST_MAPPING file to tm-dev am: 1e4e9e1c90

Original change: https://googleplex-android-review.googlesource.com/c/platform/prebuilts/sdk/+/20264551

Change-Id: I00c41bc25a5067e73658583a08dedbdcb6289850
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>