Help out with issue #11497149: Clock app crashes when opened during...

...the repeated hour in DST transition

Record the last crash info that caused an app to be marked as a bad app.

Also for the battery work, add a system property tuning parameter to be
able to control the background service start delay, so we can easily
run experiments with it turned off if we want.

Change-Id: Ic33dc464d8011c918a39b912da09ea4f0fb28874