Cleanup NN callback error handling

This CL introduces a new templated class CallbackValue to handle HIDL
"return value" callbacks in a terser and more readable way.

This CL also introduces a new macro HANDLE_HAL_STATUS to return from the
current function when an error is present with the ability to append a
more descriptive error message.

Finally, this CL changes the behavior of synchronous executions. Prior
to this CL, IPreparedModel fell back to an asynchronous execution if the
synchronous execution was allowed and failed. This change instead
returns a failure if synchronous execution is allowed and fails.

Bug: 173084343
Test: mma
Change-Id: I62714a932e71dfc77401bbcb9eaaaf3d94fb9707
Merged-In: I62714a932e71dfc77401bbcb9eaaaf3d94fb9707
(cherry picked from commit 98ed9baf)