Merge "libsnapshot: Implement OnlineKernelSnapshotWriter::OpenReader." am: b9795757e9 am: 7c1fafd7a0 am: d6e0937a1d

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1434794

Change-Id: I1f8dcec2d48be4cf3a49d62adb6f276204d72d82