Implement linkToDeath, use binder as client ID.

Implement linkToDeath for binders. Delete allocated resources for a
binder when it died or unlinked.

This CL also uses 'const AIBinder*' as client id type instead of
the callback because the Binder object corresponds to the remote
proxy and is guaranteed to be unique per client.

Bug: 204943359
Test: atest DefaultVehicleHalTest
Change-Id: If2e0c58e86a041a78b8ca69597aef4733ce1826c