Prevent system crash when adjusting volume with illegal direction

The system process crashes when any of below methods is called with
illegal direction argument:
 - MediaController.adjustVolume()
 - AudioManager.adjustVolume()
 - AudioManager.adjustSuggestedStreamVolume()

This CL fixes the crash.

Bug: 65755677
Test: Added test methods to CTS. Passed the tests.
Change-Id: I2fbf0459465c75e515110e1300630bda15e4a19e