StatsEvent annotations java autogen

Autogenerate annotations for atoms logged in java.

generated FrameworkStatsLog.java:
https://paste.googleplex.com/4789132691767296

Bug: 151102209
Test: m stats-log-api-gen
Test: m statslog-framework-java-gen
Change-Id: I50b01feaacfcb8ad5d0236432ceb0e97c8c907ab