Fix a bug where the wrong task was selected coming from home

The following behavior was buggy: Home -> toggle recents -> toggle
recents again.

This reverts to using the same model (task stack where older tasks are
first) as other Recents, and only reversing the order when placing
views on screen. Then the same logic as existing Recents implementation
can be used.

Bug: 32101881
Test: Tested behavior locally on Ryu. Existing tests should cover.
Change-Id: I52899af4581921902cd781dee707caea694d27e8