Hold a wake lock when taking bug report

Bug: 128012377
Test: Turn the screen off after initiating bugreport,
      Bugreport takes 2-5 minutes now, same takes around 30-40 minutes
      without wake lock.
Test: Added debug messages in SystemSuspend logs to confirm
      wake lock cleanup on dumpstate crash/exit.
Change-Id: Idbd2466e1d67e0157657f587cf951e9bc4a1ea05