BroadcastProcessQueue: fix wait-for-broadcast-barrier/idle

wait-for-broadcast-barrier/idle was trying to wait for
infinitely-deferred broadcasts. That's not necessary.

Test: atest WMShellFlickerTests:ExpandPipOnDoubleClickTest with barrier
Test: atest PlatformScenarioTests:android.platform.test.scenario.sysui.statusbar.StatusUpdate#testBatteryDrain
Bug: 261065790
Change-Id: Ib4de69cfd5b9cb6b36cd4d59096e9edba9b89720