Do not go home when status bar collapse is requested.

This is only invoked from CTS and related tests. Some of these tests
attempt to launch an activity and then close the status bar in the
setup step. This exits the activity and is not desired.

Test: atest GtsIncidentManagerTestCases
Test: atest CtsAutoFillServiceTestCases
Bug: 150404191
Change-Id: Ic988c537dfbb72b6eac2dc3885bb832848f8df17