Force ActivityView activities to start in new task

Activities were associating with existing tasks when their
components matched. This was causing them to be launched
into existing stacks rather than into their ActivityView. Adding
these flags forces the launches to be in unique tasks on their
ActivityView.

Fixes bug 14252286.

Change-Id: I9ba65a4a2da198435748c0a17396d3f7f8c75f5e