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: I74b4172dcf7ab4eae53cea01fcdde4b3d84df8ec
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>