Merge "Refactor and fix flaky tests in WindowOnBackInvokedDispatcherTest" into udc-dev am: f4f331d65a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23352458

Change-Id: I3c75ef2a4d56cee1310f1c0e53af90503301308c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>