Statsd dump data and metadata to bugreport

Statsd now has two dump outputs: metadata (statsdstats) and report data
(in proto form). Both are now dumped to bug reports. The former is for
debugging statsd; the latter can be used for debugging a great variety
of issues since it contains data from across Android.

Test: manual verification
Test: cts-tradefed run cts-dev -m CtsStatsdHostTestCases -t android.cts.statsd.atom.HostAtomTests#testDumpsysStats
Change-Id: Ifa5537ef22c7545a979677bc371695b37f9a75c8