Fix service tests.

Depending on a LOCAL_JAVA_LIBRARY doesn't do anything at runtime
unless the library is manually added to the class path. Since
system server classes (and the system server) can't be instrumented
like a normal app can, we can't really write "real" Instrumentation
Tests for its classes.

Given that, we can just compile the classes under test into the same
jar file as the testcases.

Change-Id: Ie4377bf81b9542ceca938e26ac78e30835fc40bc