Merge "snapuserd: use local buffers for xor processing during sync I/O" into main am: da2fc1c6af

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2670338

Change-Id: I74d7b735946334b824d88baee8ad2b3a51751e10
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>