Dynamically load statsd-service

Previously, service-statsd.jar was on the SYSTEM_SERVER_CLASSPATH. This
CL loads StatsCompanion from SystemServer.java dynamically so that the
jar does not have to be on the classpath.

Bug: 146064616
Test: boots
Change-Id: Ia0e98ed0b6e35da01b38ead2fcf45d440eae31c3
2 files changed