[automerge] libstagefright: fix heap use after free issue 2p: 2bddcbdd0c am: 55383b7c49

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

Change-Id: I8723807bfb2931ec7f64a510b366c39c2eba73a8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>