Merge "Ensure reparent activity TaskFragment is always within the same Task" into tm-dev am: 74beca1b am: 1be337bf

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18330765



Change-Id: I1b7427421049e7275a67f165a441b26501b46d16
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>