Write currentDuration into Parcel

This cl writes currentDuration to Parcel, so in battery settings we could
use this data in anomaly detection.

Also note that in getTotalDurationMsLock(aka method1), the logic is:

result = mTotalDurationMs + getCurrentDurationMsLocked(aka method2)

Since now method2 is not zero, we also tweaked the value for
mTotalDurationMs to make method1 return the same value compared with
before.

Since getMaxDurationMsLocked depends on mNesting, which is always zero,
so we don't need to tweak value for mMaxDurationMs

All these methods are covered in BatteryStatsDurationTimerTest

Bug: 64255589
Test: runtest -x BatteryStatsTest
Change-Id: I9168be099d00bb68fedbc5bfbb7bf7f0d9aae85a