[Robustness] protect get battery stats from DeadSystemException

Refine the original workaround patch in the ag/15527095 from NPE to
return default BatteryUsageStats instance as we merged in the
ag/15919139 (align the same solution).

Bug: 195306545
Test: make SettingsRoboTests
Change-Id: Ic03e8296d16ecb8629155f75727e9cde48c303eb

src/com/android/settings/fuelgauge/BatteryInfo.java

@@ -162,7 +162,9 @@ public class BatteryInfo {
                                 .getBatteryUsageStats();
                     } catch (RuntimeException e) {
                         Log.e(TAG, "getBatteryInfo() from getBatteryUsageStats()", e);
-                        return null;
+                        // Use default BatteryUsageStats.
+                        stats = new BatteryUsageStats.Builder(
+                                new String[0], /* includePowerModels */ false).build();
                     }
                 }
                 return getBatteryInfo(context, stats, shortString);