Update D8 R8 to 8.4.5-dev am: 746a24aec2 am: 806c7b03ed

Original change: https://android-review.googlesource.com/c/platform/prebuilts/r8/+/2898770

Change-Id: Ic06387f292972c8b376904fef6d951dadbab0965
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>