Flush writebooster along with manual_gc am: 356c8371ca am: 61e659e46d am: 6387e94428

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/1568873

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I06caa92c35e20c707af5a56e04be36f1fdca0ad3