Merge "No need to consider invalid tracks when checking if all active tracks are rerouted." into tm-dev am: c3e3d07b am: 47382a2a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/17142812

Change-Id: I8ca90002d841fda7c37735fd1c2d2fc56345f882