audio: rename virtualizer stage to spatializer (2) am: 1c5e2e3dd2 am: dac9046e2a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/15611202

Change-Id: I1464d57f6ec8f1d0bdf19b0980ddca025d91022b