Test home key on Razer Serval

Use wm state helper to test the home key press on the Razer Serval joystick.
The test uses WindowManagerStateHelper class to ensure that home
activity is displayed after home key is pressed.

Test: atest RazerServalTest
Bug: 136263708
Change-Id: I62fbe19c9bc3458abeec4bbfeedaf1579ac6971d
4 files changed