AudioService: better mic muting API behavior with errors

 If an error is reported when changing the microphone mute state,
log it but still fire ACTION_MICROPHONE_MUTE_CHANGED intent.
 Make AudioManager.isMicrophoneMute() return the "real" mute
state, not the intended mute state, by returning the cache
of the state returned by AudioSystem whenever a change is
attempted.

Bug: 153103117
Test: atest AudioServiceTest
Change-Id: I102f6b379eace7b396860b6f24024720fb465382