Merge "BroadcastRecord's receivers could be null." into tm-dev am: ccfcc3be

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17647259



Change-Id: I66e9502495286e010f9b3e4f378ab878bce4ba3a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>