Disable AnrTimer freezer option

Remove the freeze() option from the two clients that are currently
using it.  The functionality has already been disabled and the
implementation will be removed in a follow-on commit.

Flag: com.android.server.utils.anr_timer_freezer
Bug: 406028115
Test: atest
 * FrameworksServicesTests:com.android.server.am
 * CtsAppTestCases
 * FrameworksServicesTests:AnrTimerTest
Change-Id: I9f55c73cd041d35087dcee4f72b8dc6a8fa8bc61