Make AccessibilityService#disableSelf atomic.

This API was using a oneway aidl call, which meant that the
service was disabled some time after the method returned. That
confused tests that were turning a service off during tearDown
and then turning it back on again in setUp.

Bug: 28621277

Change-Id: I75984df0613bdbb1bc876e2a15caf59106027337
1 file changed