Merge "Try to fix IndexOutBoundsException in Task#removeChild" into rvc-dev am: e938c572b7 am: f6bc5e256e am: 71ef79b25a am: e9db7eba8b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11836345

Change-Id: I63457aeb42d4e997e918486d48f145e5684d7eee