SoundPool: Clean up attribute pointer

Test: atest SoundPoolAacTest
Test: atest SoundPoolHapticTest
Test: atest SoundPoolMidiTest
Test: atest SoundPoolOggTest
Test: atest AudioManagerTest#testSoundEffects
Test: soundpool_stress
Bug: 223815163
Change-Id: Idb2dafb9ad53dc7ffa0005425ea630fa7b7e5102
6 files changed