Resolve wait timeout in ResultDispatcher::NotifyCallbackThreadLoop

ResultDispatcher::NotifyCallbackThreadLoop wait event after event
is notified and then cause wait timeout. Patch code to check notified flag before wait.

Bug: 192460320
Bug: 192536631

Test: 1. Test basic photo shot and front/rear camera switch function
correctly. And check there is not long idle time in CLOSE stage
      2. P21 Camera Test Checklist & CTS test pass

Change-Id: Ib503bfec73a85df35368fd997a5cc835cd99c583