Merge "libbinder: Flush excess refs after single async transaction" am: e378a9e35b

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/2402157

Change-Id: I60342bd9d4d80f07a46f211293a210df148cddb0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>