Turning off accessibility feature reboots the device

1. The touch explorer uses delayed injection of events
   which can happen after its hosting accessibility
   input filer has been unregistered, thus the explorer
   was trying to inject events when this is not allowed.
   Now upon unregistration of the accessibility explorer
   it resets the state of the touch explorer it hosts.

bug:5105956

Change-Id: I720682abf93382aedf4f431eaac90fd2c781e442