Merge "libbinder: RPC simplify flush commands" am: 0204dcc52e am: b910fdcaee am: 248e989b56 am: 6b3db3de09 am: 5b1d340c12

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/1842873

Change-Id: Iab53f896fc1b543bf9e7c11de8e17801f8a63539