Merge "Enable persist.wm.debug.predictive_back_anim by default." into tm-qpr-dev am: 798eac1a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21115876



Change-Id: Ic955e616a833331aa58175ea0f3ece933e6a0089
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>