Slight refactor of AnrTimer APIs

An expired AnrTimer must be accepted with a TimeoutRecord; the call to
accept will attach any interesting expiration results to the
TimeoutRecord as the "expiredTimer".  Existing clients are changed to
use this new API.

Flag: EXEMPT refactor
Bug: 408440679
Test: atest
 * FrameworksServicesTests:AnrTimerTest
 * FrameworksServicesTests:com.android.server.am
 * FrameworksMockingServicesTests:com.android.server.am
Change-Id: Ic1e4e7726503754029e4607dfcd24335d7e38f22