Return to Home stack when a context of tasks launched from Home finished

When the following conditions happen together, another context in
Application stack was launched unexpectedly:
- There is a context of tasks in Application stack, which is launched
  from a task on Home stack.
- All tasks/activities in the context are finishing.

Solution:
Add a condition check to see if the task is NOT one of the task
finishing on-top of the top running task.

Bug: 30883775
Test: manual
Author: Ichitaro Kohara <ichitaro.kohara@sonymobile.com>
Change-Id: I5d6097a7c8dc2733ff684957370c987dd158e329