Finish crashed activities immediately

By finishing crashed activities right away the VirtualDisplays
associated with ActivityView are removed immediately rather than
being deferred. Also there is no waiting for Pause (0.5 sec) and
Destroy (10 sec) timeouts to expire.

Fixes bug 15092354.

Change-Id: Ie4941cb19dcc6f6fc61b2475162ea2794c9558a2