Fix memory leak Bug: 192998820 Test: atest VtsHalNeuralnetworksV1_2BenchmarkTestCases (with additional logging on model construction and destruction) Test: atest VtsHalNeuralnetworksV1_3BenchmarkTestCases Change-Id: Ic9f51474fac5a87265660340a8bf91b250c33887 Merged-In: Ic9f51474fac5a87265660340a8bf91b250c33887 (cherry picked from commit 3f7b316013d99808ef76c835cdca12758a82ae6e)