Merge "getActivityTokenBelow should exclude finishing activity" into sc-v2-dev am: 6a458ebd69 am: 05a96f6aae

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15650745

Change-Id: I2643c746773d3b3bbce73ffbd1b8a8ea97dfa29d