Batterystats handles nested unoptimized ble scans

When a ble scan starts, it tells batterystats whether that scan is
unoptimized. When the scan stops, batterystats is not informed of
whether the stopped scan was unoptimized. Because the ble scan call
could not be nested (couldn't call start twice without stopping first),
this was fine, but now nesting is possible, so batterystats needs to
know whether the stopped ble scan is unoptimized.

Bug: 63456783
Test: runtest -x frameworks/base/core/tests/coretests/src/com/android/internal/os/BatteryStatsTests.java
Test: no new errors when run cts-dev -m CtsIncidentHostTestCases -t com.android.server.cts.BatteryStatsValidationTest#testUnoptimizedBleScans

Change-Id: Ia73f294cf1807ddaf20f1c0bcc28add001cac78c