BatteryMonitor: get battery health data from sys file nodes am: e561d03c am:...

BatteryMonitor: get battery health data from sys file nodes am: e561d03c am: 8cc0bbf6 am: cf014940

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2317311



Change-Id: If79b82cc8d26547fdccc96e723c16199222a9fa3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>