Deliver internal server errors to the client

Due to a binder limitation (b/150808347), any unexpected exception
thrown by a binder service while processing an RPC call, will be
silently discarded and the client will get back a default-initialized
result parcelable (i.e. in most cases, won't know that anything wrong
happened).

We work around this issue by throwing a ServiceSpecificException,
which does get delivered, having a special code to designate an
internal error. Errors resulting from a HAL malfunctions will result
in a HAL reboot, which leads to recovery.

Bug: 154089179
Test: Manual verification of basic error recovery scenarios by
      injecting HAL error codes and crashes.
Change-Id: Ib5dbe08a362e545501c04204bebad5ab95f5d632