Merge changes I30d6b530,Ie2e5872a,I313cfef2,I87dfb6a0,I70709ba5

* changes:
  bootstat: add shutdown,thermal,battery
  bootstat: add reboot,2sec
  bootstat: test: check ro.boot.bootreason in some tests
  bootstat: fix test regression (exec_background)
  bootstat: fix test regression (extra logging)