interfaces/neuralnetworks: bring up to date with upstream

This CL brings the support code for NNAPI up to date with upstream, and
is compatible with the current implementation of aosp-frameworks-ml-nn.

BUG=b:187466859
TEST=FEATURES=test emerge-volteer aosp-frameworks-ml-nn

Change-Id: If6f2b26db82e03691cfff8f37f8507963d1316e2