Merge "Add new quickstep test for many tasks open at once." into sc-v2-dev am: 3c647ff30a

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15992810

Change-Id: I0ef6bd2b1f3b77a0d515610eb1f14a9fb88ae71b