Fix Car Service Test crash.

Safeguard against unregistering a broadcast reciever more than once
caused by calling cleanup successively.
Respect ICarImpl release order - should be the reverse of the init
order.

Bug: b/38046032
Test: runtest -x packages/services/Car/tests/carservice_test/
Change-Id: I79f810292100f579bc10352121c59558f5ceb0e5
(cherry picked from commit a048c0a3b653982a8a5560f9202f71cfc4d338e8)
3 files changed