Track per-process freezable state in BroadcastQueue.

This per-process freezable state will be used for deciding
when to start deferring broadcasts to a process.

Bug: 275142200
Test: atest services/tests/mockingservicestests/src/com/android/server/am/BroadcastQueueTest.java
Test: atest services/tests/mockingservicestests/src/com/android/server/am/BroadcastQueueModernImplTest.java
Test: atest ./tests/app/BroadcastsTest/src/android/app/cts/broadcasts/BroadcastDeferralTest.java
Test: atest ./tests/app/BroadcastsTest/src/android/app/cts/broadcasts/BroadcastDeliveryGroupTest.java
Change-Id: Ia480df083ed2ca213822e722fbbccaa8d6c7d33f