Camera: add a flashlight test to CTS verifier

The test turns on and off the flashlight of each camera that has a flash
unit. After it turns on and off the flashlight, it asks the user if the
flashlight is turned on or off. If the user's response is correct, it
moves to the next camera device.

Bug: 20263461
Change-Id: I762928173a80c2bdf8ec66f33e1bed60298e086d
4 files changed