This cl detects bt anomaly by using
BluetoothUnoptimizedScanBackgroundTimer. It will report anomaly
if total duration is longer than threshold.
Future cl will hook up the threshold to server side.
Bug: 36921532
Test: RunSettingsRoboTests
Change-Id: I5d6a42b2d2c4fec94387ca59ba8e6a2f3346d047