Merge "Add a unit test for a bug in registerDefaultNetworkCallback." am: b8178678df am: eabf1851e8 am: 0c0b45e6b5 am: 0ceaf95f24 am: 4c9f6a1798

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1796367

Change-Id: Ia47998f81fd73da657ec15cff1481cb1d2c7295e