Turn on new socket schema

This switches stats-log-api-gen to use StatsEvent.java and
stats_event.c/StatsLogCompat.cpp in generated StatsLog write methods.

Bug: 143979391
Test: m
Test: fastboot flashall
Test: atest CtsStatsdHostTestCases
Change-Id: I56f58d5545e51a0d7a34ec835110f5bc1b069d57