[automerger skipped] Revert "Enable mainline prebuilts on tm-dev branch." am:...

[automerger skipped] Revert "Enable mainline prebuilts on tm-dev branch." am: dddc036b -s ours am: 6d160c06 -s ours

am skip reason: Merged-In I9731400acfade95b3eab8f2d99fddb4cf856aa91 with SHA-1 4a71082e is already in history. Merged-In was found from reverted change.

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/18516629



Change-Id: Ie0c41e516f22176492ef5566dc018dec4637207b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>