RESTRICT AUTOMERGE SurfaceFlinger: fix a potential race condition in stealReceiveChannel am: a820057a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/18766123



Change-Id: I2fa98134881d1d0cd6df6dc3c0d9d19ff9ad5dfd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>