Dismiss insecure keyguards if FLAG_SHOW_WHEN_LOCKED

Windows that had FLAG_SHOW_WHEN_LOCKED and FLAG_DISMISS_KEYGUARD set
would ignore the FLAG_DISMISS_KEYGUARD if the lockscreen was
insecure. This change adds a test for insecure keyguards when the
two flags are set together.

Fixes bug 18563298.

Change-Id: I3027c7ec476d3ac15978f7e6a78b3c2050cbab02