Support new socket schema in native codegen

New code generation implementation is flag guarded by
STATS_SCHEMA_LEGACY

Support for Q schema can be added by passing --supportQ flag in
stats_log_api_gen. (Only needed for statslog_resolv.cpp)

Q schema is supported through StatsEventCompat.

Generated R schema statslog.h:
https://paste.googleplex.com/4986214782337024

Generated R schema statslog.cpp:
https://paste.googleplex.com/4856851575341056

Generated R schema statslog_resolv.h:
https://paste.googleplex.com/6062978921136128

Generated R schema statslog_resolv.cpp:
https://paste.googleplex.com/4752329251225600

Generated Q schema statslog.h:
https://paste.googleplex.com/4766729873915904

Generated Q schema statslog.cpp:
https://paste.googleplex.com/5018563779756032

Generated Q schema statslog_resolv.h:
https://paste.googleplex.com/5338897498243072

Generated Q schema statslog_resolv.cpp:
https://paste.googleplex.com/5191011011657728

Test: m -j
Test: flashes successfully
Test: adb logcat inspection
Change-Id: I5675a80c03ca3fbd5cd4a02c04a4b9cb89ec32ab