Add serialization tests for libaudioclient am: d980f658

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/2190001



Change-Id: Ib84936397d9e59c6530e369b7f6c99e78b9f606f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>