Copying some ActivityManager hidden APIs to Internal

Starting with updating references in alarm manager. Will update
references across the module in a follow up.
This is the first step to formalize them as in-process SystemApi.

Test: atest CtsAlarmManagerTestCases
atest FrameworksMockingServicesTests:com.android.server.alarm

Bug: 159382386
Change-Id: If066187bf26f1f6c532ab0f986996d427c1a17fa