Respect the virtual device recents policy.

Virtual devices can request that all activities launched on
displays owned by that device should not appear in recents.

Currently this is respected only while the display exists.
As soon as it is removed, the activities there show in the
host device recents.

This change automatically removes such activities.

Fix: 291045570
Test: atest android.virtualdevice.cts.RecentTasksTest

Change-Id: I0303b66a57f15bb23069ab441fc84684750e12e1