[3/?] Tests for generic BroadcastQueue.

Add test that verifies broadcast dispatch to registered runtime
receivers, both for single and multiple app use-cases.

Bug: 243656033
Test: atest CtsContentTestCases:BroadcastReceiverTest
Test: atest FrameworksMockingServicesTests:BroadcastQueueTest
Change-Id: Icf51e3a293efa3f7b9a5999ee37f8d80527bfb91