Fix StatsLog JNI registration

Re-add StatsLog JNI regsitration in AndroidRuntime.cpp.
This will have to be revisited once StatsLog is moved into statsd apex.

Test: m
Test: fastboot flashall
Test: adb logcat "*:E"
Change-Id: I233a527d00d524cbc2edaed7c2be76ea1c212b29