Merge "Try to fix IndexOutBoundsException in Task#removeChild" into rvc-dev am: e938c572 am: 57f60c23 am: ef2e08ce

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

Change-Id: I21f4bea2d60dc3b001466a91d2372bcc78adb063