Update D8 and R8 to 8.3.19-dev am: 9bf0129317 am: d3c876f4ce

Original change: https://android-review.googlesource.com/c/platform/prebuilts/r8/+/2843640

Change-Id: I362a3ebf99028a734c6f77bf91e6112f79521d6a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>