Merge "Don't launch placeholder for bottom TaskFragment when waiting for top" into tm-dev am: d4011e0e am: 38dbe45b am: c924a21b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17983784



Change-Id: Iaa15d009b286ea6eee2d4a82d3c412e6e6104885
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>