Merge changes from topics "nnapi-canonical-burst", "nnapi-updatable-drivers"

* changes:
  Relocate NN burst utility to ExecutionBurstUtils
  Relocate ExecutionBurst* classes to NN util code
  Implement partial canonical Burst in NN util code
  Introduce canonical IBurst object in NNAPI -- hal
  Add isUpdatable to NNAPI canonical IDevice -- hal