google_battery: record previous health active time for ac pause

1. Make sure every HEALTH_ACTIVE keeping 3 mins to estimate right time
2. Prevent enter <--> leave pause too many times

Bug: 201745988
Signed-off-by: Jenny Ho <hsiufangho@google.com>
Change-Id: Id8f9deb7ef34a11637a6d2b54a8ae6826d6402de
(cherry picked from commit d74a8a4c)