[automerge] libstagefright: fix heap use after free issue 2p: 2bddcbdd0c 2p: a648552ff0

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

Bug: 245242273
Change-Id: Id676f3befb290c47e13fa0b2d052cbb1ea97c8c9