Disable the AnrTimer freezer for broadcast ANRs

The AnrTimer can freeze ANR'ed processes until system server is ready
to take a stack dump.  The process is unfrozen when the ANR report is
generated.  The process is also unfrozen in a finalizer, in case
system_server fails to take an ANR report.  However, the unfreeze
operation can induce a finalizer timeout.

This change disables freezing ANR'ed processes until the finalizer
timeouts are understood.

Flag: com.android.server.utils.anr_timer_freezer
Bug: 386408143
Test: atest
 * FrameworksServicesTests:com.android.server.am
 * CtsAppTestCases
 * FrameworksServicesTests:AnrTimerTest
Change-Id: I0a53f8e67a1debd615c36b439e2b151a8aceb910