Attribute procstate cpu times to correct battery/screen on/off buckets.

- Remove redundant 'mPluggedCounts' data from LongSamplingCounterArray
- Update relevant tests

Bug: 66953194
Test: atest core/tests/coretests/src/com/android/internal/os/BatteryStatsTests.java
Test: atest hostsidetests/incident/src/com/android/server/cts/BatteryStatsValidationTest.java
Test: atest core/tests/coretests/src/com/android/internal/os/BstatsCpuTimesValidationTest.java
Change-Id: I1f32eef0d4a0fe3b6124c07d016cf0ff8967b956