Update ServiceState.hashCode()

hashCode() was missing about 10 fields and was
using some unnecessary bespoke logic to generate
hashes for individual fields. This CL simplifies
the hashCode() implementation and adds the missing
fields.

Bug: 8675309
Test: compilation
Change-Id: I1424973b11fcc6480d6f8c83d5fd0eb1b5533c7f