audio: Change mDeathHandler from a member into a local variable am: 17b3201259 am: 6fcb2f8d81 am: bc7bd65a78

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2819040

Change-Id: I66f09c296d12b1132bfb23e1bfb502f7a3eba882
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>