Fix memory leak

Bug: 166073521
Test: atest VtsHalNeuralnetworksV1_2BenchmarkTestCases (with additional logging on model construction and destruction)
Test: atest VtsHalNeuralnetworksV1_3BenchmarkTestCases
Change-Id: I5c8ed9879d748cc15e95a454bcb4362b66b2c5d2
Merged-In: I5c8ed9879d748cc15e95a454bcb4362b66b2c5d2
(cherry picked from commit 78819052d898cdfe77033dbe59e0839a092f80a9)
2 files changed