Add PACK operation to NNAPI feature level 6.

Cherrypicked from Ic15d047b70c62437b4f0db6f2ca10127591ae07c

Bug: 206089870

Test: m -j NeuralNetworksTest_static
Test: VtsHalNeuralnetworksTargetTest

Change-Id: Ic15d047b70c62437b4f0db6f2ca10127591ae07c
Merged-In: Ic15d047b70c62437b4f0db6f2ca10127591ae07c
(cherry picked from commit 0af4ac2ec4bc4f0d95ad412480593710260af6e8)
2 files changed