OomAdjuster Freeze Handling with CPU capability

Introduce PROCESS_CAPABILITY_CPU_TIME which is intended to mark what
processes are guarenteed to run on the cpu. Also create the concept of
Freeze Poicy within OomAdjuster to control the decision to freeze
processes.

Flag: com.android.server.am.use_cpu_time_capability
Bug: 370817323
Test: atest MockingOomAdjusterTests
Change-Id: Id548e44306851690c96a0d87d47039eafbd8c453