FL7: Add REVERSE CPU reference implementation and functional testing am: 2f6689aae5

Original change: https://android-review.googlesource.com/c/platform/packages/modules/NeuralNetworks/+/1956740

Change-Id: I08a942269daf0e9231ab8e24db5350c0ed50d5bb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>