stagefright: fix unreleased OMX handle

- Ensure OMX handle is freed even if binder death notification comes
first.
- Add DeathRecipient in ResourceManagerService so that it could
handle dead clients properly.

Fix: 28824626
Fix: 34252788
Test: adb shell am instrument -e size small -w 'android.media.cts/android.support.test.runner.AndroidJUnitRunner'
Change-Id: Ifc441a2771b5674749ff65a4520177dda115b292