Remove legacy useless BatteryTip cache mechanism

Remove the legacy BatteryTip list cache mechanism to avoid not using the
new re-create BatteryTip list, but only update its state and invoke
updatePreference(). We should use the new BatteryTip list to apply the
new detected results.

Test: make -j64 RunSettingsRoboTests ROBOTEST_FILTER="com.android.settings.fuelgauge.batterytip"
Change-Id: I884f04927403ad4d97b459ff5477a1fe9df21553