Handle binder death with the conductor rather than VibrationThread.

The conductor is directly associated with the vibration+binder token,
unlike the thread, so the signal is guaranteed to be correctly attributed.

Bug: 193792066
Test: atest, presubmit
Change-Id: I34bdf2c942e1c8e0db9526c9e84e92f69718f4b4
3 files changed