Merge changes from topic "nnapi-aosp-sync"

* changes:
  NNAPI: Add execution preference to prepareModel (HAL)
  Sync NNAPI Operand and Operation documentation fixes
  Fix the spec for TENSOR_QUANT8_ASYMM to match our validation.
  Fix the NNAPI HAL documentation about ADD and MUL
  NN validation tests
  Add validation tests for consistency of model inputs and outputs.
  Disable arm32 asan for VtsHalNeuralnetworksV1_1TargetTest