NNAPI: Add execution preference to prepareModel (runtime)

A model can be compiled in different ways to optimize for different
use-cases. This CL propagates the execution preference across the HAL so
that the NN service can better fit the users needs.

Bug: 77864669
Test: mma
Test: NeuralNetworksTest_static
Test: VtsHalNeuralnetworksV1_1TargetTest
Merged-In: I93079b18224ea10cb0a23bfbdc1ed80e302071a8
Change-Id: I93079b18224ea10cb0a23bfbdc1ed80e302071a8
(cherry picked from commit 1e966620)