[automerge] libstagefright: fix heap use after free issue 2p: 2bddcbdd0c am: 55383b7c49 am: ede04005ea am: 5910d09c44 am: 349c2e28d9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/20068332

Change-Id: Ie1e33428aae34903b17463619a5d3540ae52e6c7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>